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Oral presentation abstracts

Engineered Interfaces

KEY-EI

Engineering stability through interfacial rheology: where do we stand?

Jan VERMANT

Department of Materials, ETH Zürich, Switzerland

Stability of thin films (as in foams and emulsions) can be engineered by the surface active components

which accumulate in the interfacial region. There are different aspects which can be changed, which include

the compressibility of the interface, the absolute value of surface tension, or imparting rheological

properties at the interface, either in shear or dilation. Under some conditions, the different possible

contributions can be separated. Special emphasis will be given to interfaces where the extra rheological

stresses can be influenced by engineering the colloidal interactions at the interface.

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EI-1

Adsorption kinetics and interfacial rheology as a means to tune the microstructure of citrus

pectin emulsions

Ulrike S. SCHMIDT1, Heike P. SCHUCHMANN1 1 Food Process Engineering, Karlsruhe Institute of Technology, Institute of Process Engineering in Life

Science, Karlsruhe, Germany

With world market prices being unstable and permanent hygienic issues at hand, the beverage industry is

eager to find a replacement for the hydrocolloid gum arabic which is widely used to stabilize food

emulsions. Pectins might be a possible solution to this challenge particularly since it has been shown that

much lower quantities are necessary to achieve the same stabilizing effect as with gum arabic.

Recently, we showed that citrus pectins with different degrees of methylesterification can be a promising

alternative1,2. However, for a successful replacement of gum arabic, thorough knowledge of pectin’s

emulsifying properties is necessary.

The varying amount of pectin’s methylester groups in combination with different pH and ionic strength can

be used to tune colloidal properties such as zeta potential or hydrodynamic radius of the molecules. We

will show that a proper choice of formulation allows for a targeted alteration of the adsorption kinetics and

dilational rheological properties of citrus pectin. A direct correlation with the emulsifying and stabilizing

properties can be achieved. As long as bridiging flocculation can be avoided at low ionic strength, fast

adsorption kinetics and dominantly elastic oil-water interfaces lead to the creation of finely dispersed

emulsions that are very stable. We will compare the results with those gained from trials with gum arabic

under comparable conditions in order to show the potential of pectin in typical food applications.

References

1) Schmidt, U.S., Koch, L., Rentschler, C., Kurz, T., Endreß, H.-U. and Schuchmann, H.P. (2014). Effect of Molecular

Weight Reduction, Acetylation and Esterification on the Emulsification Properties of Citrus Pectin. Food Biophysics,

doi: 10.1007/s11483-014-9380-1

2) Schmidt, U.S., Schmidt, K., Rentschler, C., Kurz, T., Endreß, H.-U. and Schuchmann, H.P. (2014). Pectins of different

origin and their performance in forming and stabilizing oil-in-water-emulsions. Food Hydrocolloids, doi:

10.1016/j.foodhyd.2014.12.012

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EI-2

Experimental exploration of triglyceride ordering at surfactant-covered oil-water interfaces

Nicole L. GREEN1, Dérick ROUSSEAU1, Stephen R. EUSTON2 1 Department of Chemistry & Biology, Ryerson University, Toronto, Canada 2 School of life Sciences, Heriot-Watt University, Edinburgh, Scotland

Triglyceride crystallization behavior at an oil-water interface in the presence of emulsifier and fat has been

directly observed using a temperature-controlled tensiometer. Recent experimental observations by Ghosh

et al. [1] have suggested that the similar molecular structures of glycerol monooleate (GMO) and

hydrogenated canola oil (HCO) promoted the formation of interfacial crystals, leading to water-in-oil

emulsions simultaneously stabilized by Pickering and network-type crystals. [1] Without surfactant (HCO

only) or with surfactant lacking molecular complementarity (HCO + polyglycerol polyricinoleate (PGPR)),

interfacial crystallization was not promoted. We carry out experiments in similar systems, testing the

effects of surfactant-fat complementarity by using PGPR, GMO, and glycerol monostearate (GMS). We use

a tensiometer to create a water droplet within the oil medium, akin to a water-in-oil emulsion. We find

that, in the absence of surfactant, fat lacks the surface activity to preferentially crystallize at the interface

and will nucleate spontaneously in the bulk oil. Conversely, the addition of surfactant can yield full, partial,

or no crystallization interfacial crystallization depending on the chosen surfactant and surface coverage.

The results are compared to accompanying molecular dynamics simulations conducted by Euston in a

separate presentation.

[1] Ghosh, S. and Rousseau, D. Cryst. Growth Des. 2012, 12, 4944–4954

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EI-3

Sesame proteins for microbubble foams

Miro KIRIMLIDOU1, Christos AMPATZIDIS2, Thodoris D. KARAPANTSIOS2, Vassileios KIOSSEOGLOU1,

Constantinos V. NIKIFORIDIS3 1 Food Chemistry and Technology, School of Chemistry, Aristotle University, Thessaloniki, Greece 2 Chemical Technology, School of Chemistry, Aristotle University, Thessaloniki, Greece 3 Biobased Chemistry and Technology, P.O. Box 17, 6700 AA Wageningen, the Netherlands

Microbubble engineering is one of the emerging scientific topics, due to the numerous potential

applications in medical science and foods.1 Most of the cases, complex materials have to be used as

stabilizers, therefore the formation of microbubble foams with natural ingredients is a challenging field.

Moreover, plant protein-stabilized foams have attracted considerable research interest due to their

sustainable production and potential technology applications.2

In this work, highly efficient, green fractionation practices have been developed for producing sesame seed

isolate, containing 96 wt% proteins. Physico-chemical characterization of the isolate showed that it is

mainly comprised of relatively low molecular weight hydrophobic proteins, soluble at alkaline pH values

and ionic strengths above 0.25 M.

The adsorption behaviour of sesame proteins at air-water interfaces was investigated by employing static

and dynamic surface tension measurement techniques. Sesame proteins exhibit an outstanding ability to

drastically decrease the surface tension, even at very low concentrations. Furthermore, their presence in

aqueous solutions at very low concentrations such as 0.06 wt% was enough to produce stable microbubble

foams, by ultrasonication. The foam stability was evaluated by monitoring the evolution of bubble size. The

results pointed to a remarkable stability of the sesame seed foams, which retained 25% of their initial

volume even 28h after their production.

Finally, all the above research has given insights in the mechanisms behind foam stabilization by sesame

seed proteins, such as interfacial asorption and lamella viscosifying, This work could have direct

impilications in the production of sophisticated, health promoting and stable aired products.

1. Swanson, E. J., Mohan, V., Kheir, J., & Borden, M. A. (2010). Phospholipid-Stabilized Microbubble Foam for

Injectable Oxygen Delivery. Langmuir, 26 (20), 15726-15729.

2. Nikiforidis, C. V., Ampatzidis, C., Lalou, S., Scholten, E., Karapantsios, T. D., & Kiosseoglou, V. (2013). Purified

oleosins at air-water interfaces. Soft Matter, 9 (4), 1354-1363.

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EI-4

Microbubbles Stabilised by Mixtures of Hydrophobin + Casein : Experimental Results and

Theoretical Considerations

Rammile ETTELAIE1, Pappole VALADBAIGI1, Brent MURRAY1 1 Food Colloids Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK

Long term stabilisation of small bubbles of micron size dimensions remains a particularly challenging

problem in colloid science generally, and in food colloids more specifically. While in recent years the

Pickering stabilisation mechanism has been explored as one of the promising routes to overcoming this

problem, the lack of very fine edible nanoparticles, with appropriate surface chemistries, so far has limited

this approach in foods. The fungal protein hydrophobin, possessing a highly globular structure that does

not unfold upon adsorption at air-water interfaces, may provide one possible solution forward. The idea is

that the interfacial behaviour of hydrophobin is in many respects closer to that of a genuine nanoparticle

rather than a typical biomacromolecule. However, at present the price of hydrophobin is quite expensive.

Therefore it is of some practical importance that this protein is utilised in the most efficient way. To this

end, we report here on stabilisation of microbubbles achieved by a combination of hydrophobin + casein.

It is found that at an optimum mix ratio of the above two proteins, small microbubbles with excellent long

term stability can be realised. Furthermore, these are produced upon application of relatively moderate

levels of shear. That such small micron sized bubbles can be generated under such shearing conditions

points to the possibility that the bubbles incorporated are originally much larger, but that they

subsequently shrink and become stable at a much smaller size. We present theoretical calculations,

analysing the problem of shrinkage of bubbles in the presence of such nanoparticles, where the

concentration of particles happens to be small. We show that the effect of shrinkage, followed by stability,

arises from the interplay between the kinetics of bubble dissolution, the rate of arrival and adsorption of

the nanoparticles onto the surface of the bubbles, and the competition of different sized bubbles to gather

a sufficient number of particles required to stabilise them [1,2].

[1] Ettelaie R; Murray BS, Journal of Chemical Physics 140 204713-1-204713-13,2014

[2] Ettelaie R; Murray BS, Colloids and Surfaces A: Physicochemical and Engineering Aspects 475 27-36, 2015.

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EI-5

Interaction of Hydrophobins with Other Surface Actives in Ice Cream and Effect on Bubble

Stability (A Surface Rheology Perspective)

Damiano ROSSETTI1, Nick HEDGES1, Andrew COX1 1 Unilever R&D Colworth, Sharnbrook (Bedford), UK

Ice cream (IC) consists of several phases, including gas bubbles, whose microstructural integrity is key for

consumer experience. Class II Hydrophobins (HFBII) from Trichoderma reesei (filamentous fungi) are novel

small proteins imparting exceptional stability to liquid foams [1,2] owing to the high surface elasticity at the

air-water interface [2-4]. IC, however, contains other surface actives (milk proteins) that may impair HFBII

functionality. Here we discuss HFBII surface properties in context with stability of IC microstructure under

conditions of thermal abuse, which accelerates degradation of gas bubbles. Major findings are:

Surface elasticity of HFBII/SMP (skim milk powder) solution is reduced in comparison to the case of HFBII

alone. This affects microstructure of IC containing both actives after temperature abuse.

Addition of non-ionic surfactant Tween20 to HFBII/SMP mix produces a recovery of surface elasticity and

an improvement in gas bubble stability of IC after temperature abuse

The HFBII/Tween20 complex formed at the air-water interface has lower interfacial tension and higher

surface elasticity than the HFBII/SMP mix; the former then dominates the interface when the three

ingredients are present together, with stability improvement in the gas phase

These results are backed up by Cryo-SEM images.

References

1) Cox, A. R., Cagnol, F., Russell, A. B. et al., (2007), Surface properties of class II hydrophobins from Trichoderma

reesei and influence on bubble stability, Langmuir, 23, 7995-8002

2) Cox, A. R., Aldred, D. L., Russell, A. B., (2009), Exceptional stability of food foams using class II hydrophobin HFBII,

Food Hydrocolloids, 23, 366-376.

3) Blijdenstein, T. B. J., Ganzevles, R. A., De Groot, P. W. N. et al., (2013), On the link between surface rheology and

foam disproportionation in mixed hydrophobin HFBII and whey protein systems, Colloids and Surfaces A:

Physicochemical and Engineering Aspects, 438, 13-20.

4) Kloek, W., van Vliet, T., Meinders, M., (2001), Effect of bulk and interfacial rheological properties on bubble

dissolution, Journal of Colloid and Interface Science, 237, 158-166

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EI-6

Creation of textured dairy emulsions by connecting oil droplets through whey protein

aggregates

Thibault LOISELEUX1, Catherine GARNIER1, Thomas CROGUENNEC2, Valérie BEAUMAL1 Camille

JONCHERE1, Marc ANTON1, Alain RIAUBLANC1 1 UR1268 INRA, Biopolymères Interactions Assemblages, Nantes, France 2 UMR 1253 INRA, Science and technologie of milk and egg, Rennes, France

Heat treatment applied on whey proteins solutions causes protein denaturation and induces the formation of aggregates of different sizes and shapes depending on the experimental conditions. Even if cold gelation of whey protein aggregates is well known [1], their role in emulsions and their interfacial properties are less studied. Recent works showed that emulsions containing 30% of milk fat can be textured by modulating the ratio Aggregates (Ag)/Native Whey Protein (NWP) and by taking into account the size and the distance between droplets [2]. Based on these results, our challenge in this study was to texture emulsions with low oil volume fractions using aggregates We investigated the texture of dairy emulsions composed of 5-30% (w/w) of milk fat stabilized by a mixture of fractal aggregates having an average size of 240 nm and NWP. After homogenization (500 bars), emulsions were analyzed at 20°C by visual observation, granulometry, confocal laser microscopy and dynamic oscillatory measurements. When oil content was 30%, emulsions were already textured after homogenization at 60°C which is in contrast with 5% oil-in-water emulsions that remain liquid. Surprisingly, these low oil content emulsions texturize over time with increasing firmness. It is suggested that Ag allows the formation of a network by connecting oil droplets leading to emulsion texture. Tuning the Ag/NWP ratio induces very different textures for these low oil content emulsions ranging from heterogeneous systems exhibiting syneresis for 2 and 0.1% (w/w) of Ag and NWP respectively to smooth and stable emulsions for 3% of Ag and the same proportion of NWP. Confocal laser microscopy evidenced a rough microstructure with serum pores for emulsions with 2% of Ag and 0.1% (w/w) of NWP (Figure 1A) whereas more homogeneous systems were observed for 3% of Ag (Figure 1B). Moreover, rheological properties of these emulsions are recovered after shearing that could be very interesting for food application perspectives (Figure 1C). In conclusion, tuning Ag/NWP ratio can be a tool to control and guide emulsion texture even at low oil volume fraction by creating a network. In this way, fractal aggregates may be an alternative to additives use in dairy emulsions.

[1] V. Leung Sok Line, G. E. Remondetto, and M. Subirade, “Cold gelation of β-lactoglobulin oil-in-water emulsions,”

Food Hydrocoll., vol. 19, no. 2, pp. 269–278, 2005.

[2] C. Surel, J. Foucquier, N. Perrot, A. Mackie, C. Garnier, A. Riaublanc, and M. Anton, “Composition and structure of

interface impacts texture of O/W emulsions,” Food Hydrocoll., vol. 34, pp. 3–9, 2014.

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EI-7

The influence of size and concentration of silica particles and salt on foaming property of

casein/silica system

M. CHEN1,2, G. SALA1,2,3, M.B.J. MEINDERS1,3, E. VAN DER LINDEN1,2 1 Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, The Netherlands 2 Wageningen UR, Physics and Physical Chemistry of Foods, P.O. Box 17, 6700 AA Wageningen, The

Netherlands 3 Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen, The Netherlands

Previous research indicated that casein micelle aggregates have a large influence on foam stability of casein

micelle dispersions. However, to what extend the amount of aggregates and their size influence the

foaming properties is not clear yet. In this study, we used silica particles with different sizes (10 nm, 200

nm, 1 µm and 5 µm) to mimic casein micelle aggregates and mixed them with casein in different ratios at

pH=6.7. Samples were characterized for particle size, shear viscosity and microstructure by SEM.

Furthermore, the effect of different concentrations of NaCl (50 mM, 100 mM and 200 mM) was

investigated. Foamability and foam stability of samples were tested by foamscan. Thin film structure and

stability were also investigated by CLSM and micro interferometry. By analysing correlations between the

data obtained with these experiments, we assessed the role of particle size and concentration on foaming

properties of casein/silica mixture and uncovered the interaction between casein and silica particles under

different conditions.

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EI-8

A novel measurement device for investigating the shelf life of single and double emulsions

Susanne NEUMANN1, Heike P. SCHUCHMANN1 1 Karlsruhe Institute of Technology, Institute of Process Engineering in Life Science, Section 1: Food Process

Engineering, Karlsruhe, Germany

Water in oil in water (W1/O/W2) double emulsions consist of an inner water in oil (W1/O) emulsion which is

in turn dispersed in an outer continuous aqueous phase. Due to this structure, W1/O/W2 double emulsions

have a great potential in Life Sciences for the encapsulation of e.g. bioactive compounds or the production

of fat reduced products.

In general double emulsions are produced in a two step process. At first, the inner water phase is dispersed

in the intermediate oil phase by using high shear rates. In a second step, the inner emulsion is dispersed in

the outer aqueous phase using lower shear rates.

The complex structure offers a great application potential, but it also gives reason for thermodynamical

instability. Therefore, only a few products entered commercial markets today.

Irreversible instability phenomena of high importance are coalescence between the similar aqueous phases

and diffusion of water molecules through the oily membrane to the outer phase.

This leads to a loss of the inner aqueous phase until the typical double emulsion structure is entirely lost.

The release of inner water phase is quantified by the encapsulation efficiency (EE). EE describes the mass

ratio between the water content at a specific time and the initial inner water content.

To avoid instabilities, different surfactants e.g. emulsifiers, stabilizers and salts might be added. The

selection of these compounds is mainly based on experience and not on mechanistic understanding. A

specific challenge arises from the fact that these additives interact with themselves. This leads to a change

of the interfacial properties, e.g. interfacial tension, interfacial elasticity and kinetics of adsorption, and

thus influence the shelf life of double emulsions.

We designed an experimental setup that allows us to investigate the interactions of specific formulation

additives. This makes it possible to differentiate whether the inner aqueous phase is lost by diffusion or

coalescence.

The experimental design will be presented in this contribution. Using model systems, we will also depict

first results on investigations on the influence of different additives.

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EI-9

EPR spin probing to characterize the impact of inferfaces during lipid oxidation

Heimke KRUDOPP1, Anna Mielke1, Anja STEFFEN-HEINS1 1 Institute of Human Nutrition and Food Science, Kiel University, Kiel, Germany

The inhibition of lipid oxidation in multiphase systems depends on several factors such as the location of

antioxidants and their chemical microenvironment that is defined by the characteristics of the emulsifier

used.

The characteristics of the interfaces affecting the generation of free lipid radicals as well as the antioxidant

reduction capacity were investigated by means of electron paramagnetic resonance spectroscopy (EPR).

Nitroxide radicals were used as spin probes which are sensitive to their chemical microenvironment and

can also react as antioxidants. In dispersed systems, nitroxide radicals give rise to the detection of the

coexistence of different rotational motions and polarities of probe populations, which results in EPR spectra

composed of several superimposed spectral components. By means of lineshape analysis, the

micropolarity, microviscosity, structural order of the environment and the proportion of nitroxides for each

spectral population can be obtained which are indicative for a characteristic solubilization site in emulsions

[1]. Deconvolutions were carried out by adoption of different biophysical models as a function of the

population mobility by using the software EPRSIM-C of Štrancar and colleagues [2].

In terms of nitroxide reduction kinetic, TEMPO was reduced the fastest by antioxidants compared with

TEMPOL and TEMPOL-benzoate (TB) which may be due to a different alignment of the nitroxides in the all

interfaces investigated. While TEMPO may align with the NO moiety to the more hydrophilic part of the

interface, TB and TEMPOL possess more hydrophilic groups that may be accommodated in the hydrophilic

region leading to a 180° rotation with the NO moiety incorporating in the more nonpolar region of the

palisade layer.

The nitroxide TEMPO is oxidized by alkyl radicals, however, monitoring of alkoxyl radicals is not suitable for

nitroxides as they react too slowly. We conclude that the distinct location and orientation of the nitroxide

in the interface is likewise the prerequisite for the reaction with lipid alkyl radicals indicating different

solubilization sites of free ipid radicals in food as a function of their species and structural composition.

[1] H. Krudopp and A. Steffen-Heins, J Colloid Int. Sci., 2015, 452: 15-23

[2] J. Strancar et al, J Chem Inf Model, 2005,45(2): 394-406.

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EI-10

Stability of lycopene-loaded emulsions: Effect of dairy and plant proteins at the interfaces

Kacie K.H.Y. HO1,2, M. Fernanda SAN MARTIN GONZALEZ1, Karin SCHROEN2, Claire C. BERTON-

CARABIN2

1 Purdue University, West Lafayette, Indiana, USA 2 Wageningen University, Wageningen, NL

Evidence has shown that consuming bioactive phytochemicals reduces the risk for various diseases 1,2.

Unfortunately, stability in foods and delivery in vivo often has challenges. In this study we investigate

lycopene, the primary carotenoid in tomatoes, which has been associated with reducing the risk of cancer,

but is susceptible to oxidation and has poor bioaccessibility due in part to its hydrophobicity. In order to

improve the stability and bioaccessibility of bioactives, delivery strategies should be developed and for that

mechanistic understanding is of utmost importance. In the case of lycopene, oil-in-water (O/W) emulsions

could be used to solubilize hydrophobic compounds to improve uptake and absorption. Dairy proteins have

successfully been used to stabilize many emulsions3, but plant proteins could be interesting alternatives

due to their wide availability, lower cost, and lower impact on the environment. Thus, this research aimed

to determine the effects of interfacial protein on the physical stability and lycopene retention in canola

O/W emulsions..

The physicochemical stability of these emulsions was measured for dairy (whey protein isolate, sodium

caseinate) and plant (soy and pea protein isolate) proteins. Droplet size and charge were measured over

time and chemical stability was studied by determining lycopene content and the extent of lipid oxidation

via conjugated dienes and para-anisidine value. Dynamic interfacial tension measurements were carried

out to compare the functionality of all proteins in regard to emulsion formation. All proteins were able to

reduce the interfacial tension in a similar way, and at comparable rates; the plant proteins showed

promising behaviour. Dairy and plant protein emulsions exhibited particle sizes within the same order of

magnitude (~130-200 nm). Overall, whey protein isolate and sodium caseinate produced smaller, more

stable emulsion droplets compared to plant proteins, but the differences were not that great. Interestingly,

emulsions stabilized with plant-based proteins appeared to exhibit better chemical stability compared to

dairy protein, and this is most probably linked to specific interactions with lycopene.

In summary, the physicochemical stability of lycopene-loaded emulsions can be modulated by interfacial

composition, which may be applied to multi-effect delivery systems for lycopene and other lipophilic

bioactives..

1. Steinmetz & Potter (1996). J of ADA, 96(10), 1027-1039.

2. He et al. (2007). J Hum Hypertens, 21(9), 717-728.

3. Mao et al. (2009). Food Tech Biotech, 47(3), 336-342.

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EI-11

Behaviour of Pickering emulsions stabilized by soft whey protein microgel particles during in

vitro gastrointestinal digestion: Impact of heat treatment

Anwesha SARKAR1, Brent MURRAY1, Melvin HOMES1, Rammile ETTALAIE1, Azad ABDALLA1, Xinyi

YANG1 1 Food Colloids and Processing Group, School of Food Science and Nutrition, University of Leeds, LS2 9JT,

United Kingdom.

Emulsions stabilized by soft whey protein microgel particles have gained research interest due to their

combined advantages of biocompatibility and high degree of resistance to coalescence. We designed

Pickering oil-in-water emulsions using whey protein microgels using a facile route of heat-set gel

formation followed by mechanical shear and studied the influence of heat treatment on emulsions

stabilized by these particles. The aim of this study was to compare the barrier properties of the microgel

particles and heat-treated fused microgel particles at the oil-water interface in delaying the digestion of the

emulsified lipids using an in vitro digestion model. A combination of transmission electron microscopy and

surface coverage measurements revealed increased surface of heat-treated microgel particles at the

interface. The heat-induced microgel particle aggregation and therefore, a fused network at the oil-water

interface was more beneficial to delay the rate of digestion as compared to that of intact whey protein

microgel particles in presence of pure lipase and bile salts, as shown by measurements of zeta potential

and free fatty acid release, plus theoretical calculations (Figure 1). However, simulated gastric digestion

with pepsin impacted significantly on such barrier effects, due to the proteolysis of the particle network at

the interface irrespective of the heat treatment, as visualized using sodium dodecyl sulfate polyacryl amide

gel electrophoresis measurements.

Figure 1. Kinetics and schematic diagram of proposed mechanism of fatty acid release (lipolysis) from 20 wt% O/W emulsions stabilized whey protein microgels (solid circles) with or without heat treatment (open circles) when they are exposed to pure lipase and bile salts. Kinetics (theoretical fit) of lipolysis of whey protein stabilized emulsion (gray solid line) with or without heat treatment (black dashed line). Insets represent transmission electron microsgraphs. Error bars denote standard deviation of three measurements.

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EI-12

Interfacial aspects underlying the inhibitory effects of Green Tea extract on lipolysis in-vitro

Teresa DEL CASTILLO-SANTUELLA1, Julia MALDONADO-VALDERRAMA1, Deyanira RONDON-

ROGRIGUEZ2, MaJose GALVEZ-RUIZ1, Miguel Angel CABRERIZO-VILCHEZ1

1 University of Granada, Department of Applied Physics, Campus de Fuentenueva, sn., 18071 (University of

Granada, Granada, Spain) 2 Biosearch Life S.A. Department of Biotechnology. Camino de Purchil, 66., 18004 (Biosearch Life S.A.,

Granada, Spain)

Inhibition of lipase activity is one of the approaches to reduced fat intake with nutritional prevention promoting healthier diet. Literature works have shown that tea and phenolic components such as catechins from tea have antiobesity and antidiabetic effect in humans, reduce adipose mass in rodent models, and influence lipid digestion in vitro [1]. In this work we evaluate the inhibition of lipolysis provided by a Green Tea Extract (GTE) provided by Biosearch Life S.L. To this end, we have used a novel methodology to investigate the interfacial mechanism underlying the inhibition of lipolysis of GTE [2]. The inhibitory potential is first correlated with the reduction of the interfacial activity of lipase and also compared with commercial inhibitor (Xenical®). Then, the dilatational response of the mixture lipase/GTE allows identification and discussion of the specific mode of action of GTE on lipase. Our results suggest that GTE operates by inducing conformational changes in the molecule which can be quantified by the dilatational response. The interfacial tension study provides new insights into the mechanism underlying the inhibition of lipase by GTE and allows optimising the concentration to be used in food formulations [2].

Acknowledgements: This work has been funded by CDTI (Center for the Development of Industrial Technology) and cofinanced with FEDAER funds (FEDER INNTERCONECTA: ITC-20131081), RYC-2012-10556, MAT2014-60615-R, MAT2012-36270-C04-02, COST-MPN-1106-Green Interfaces, CEI BIOTIC BS14.2015, and CEI BIOTIC BS28.2015. References: [1] Inhibitory effect of oolong tea polyphenols on pancreatic lipase in vitro. M. Nakai, Y. Fukui, S. Asami, Y. Toyoda-Ono, T. Iwashita, H. Shibata, T. Mitsunaga, F. Hashimoto, Y. Kiso. J. Agric. Food Chem. 2005, 53 (11), 4593-4598 [2] Natural Inhibitors of Lipase: Examining Lipolysis in a Single droplet. T. del Castillo-Santaella, J. Maldonado-Valderrama, M.A. Cabrerizo-Vilchez, C. Rivadeneira-Ruiz, D. Rondon-Rodriguez, M.J. Galvez-Ruiz. J. Agric. Food Chem. In press (DOI: 10.1021/acs.jafc.5b04550)

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Physical Aspects of Oral Processing

KEY-OP

Food structure, oral processing behaviour and dynamic texture perception

Markus STIEGER1,2 1 Wageningen University, Division of Human Nutrition, P.O. Box 8129, 6700 EV Wageningen, The Netherlands 2 TI Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, The Netherlands

Oral processing is key to dynamic sensory perception as food properties are constantly transformed during

consumption from first bite to swallow. Food structure is broken down by oral processing and contributes

to dynamic perception of texture, taste and flavour. The transformations depend on the physical-chemical

properties of the foods, the human physiology and the oral processing behaviour of the individual

consumer.

Food oral processing as the bridge between the transformation of food structure during consumption and

its association with dynamic sensory perception has gained enormous interest in the last decade. An

overview of the interplay between the structure of liquid and semi-solid foods, oral processing behaviour

and dynamic sensory perception is provided. Semi-solid model gels are described as suitable foods to

systematically investigate these relationships. Physical-chemical and rheological characterizations of bolus

properties of a variety of foods are discussed in relation to oral processing behaviour and sensory

perception. Special emphasizes is given on the influence of food structure on oral processing behaviour.

Oral processing behaviour can be characterized by methodologies such as Electromyography (EMG) to

monitor muscle activity, jaw tracking techniques to monitor spatial displacement of the jaw and

Electromagnetic articulography (EMA) to monitor tongue movements during oral processing. Oral

processing behaviour during drinking of liquids and mastication of semi-solid foods can be influenced by

modifications of the food structure. Oral processing behaviour is adaptive and consequently changes with

the changing properties of the bolus in the mouth. Recently, it was suggested that food preferences and

mastication behaviour might be linked and consumers were grouped based on their preferred chewing

behaviour. Preferred chewing time of a specific food varies between consumers and can determine the

properties of the bolus and can explain difference in dynamic texture perception between consumers. This

allows to design specific breakdown pathways of foods which are associated with desired dynamic sensory

properties and to develop foods for specific consumer groups by designing foods which match the

structural breakdown to the preferred oral processing behaviour.

Food Colloids 2016

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OP-1

Oral processing of food – structure breakdown and reorganisation

Sofia KIHLMAN ØISETH1, Graham EYERS2,3, Li DAY1,4, Leif LUNDIN1,5, Ingrid APPELQVIST2

1 CSIRO, 671 Sneydes road, Werribee, VIC 3030, Australia 2 CSIRO, 11 Julius Avenue, North Ryde, NSW 2113, Australia 3 Present affiliation: Department of Food Science, University of Otago, Dunedin, New Zeeland 4 Present affiliation: AgResearch, Palmerston North, New Zealand 5 Present affiliation: SP Food and Bioscience, Gothenburg, Sweden

We have been studying the oral breakdown of various food products (cheese, breakfast cereal, snack foods

and gels) to obtain information of how the food is naturally processed in mouth in preparation for

swallowing. Food samples were chewed by volunteers until the urge to swallow point or for shorter

intervals to follow the breakdown from solid pieces of food, through incorporation of saliva, to the

formation of a mass that could be swallowed. The chewed food was spat out and collected under strict

biohazard protocols. In conjunction with collection of naturally masticated samples, food samples were

placed in thin plastic bags and chewed upon to investigate the oral breakdown without the influence of

saliva. Masticated samples were analysed to determine particle size distribution by sieving or image

analysis and microstructural changes was investigated by microscopy.

The oral breakdown of food is clearly related to the formation of a material that is physiologically safe to

swallow. We found that a material that forms a bolus required much less chewing to get to the point of

swallowing compared to a food that breaks down into individual non-cohesive particles. Furthermore, for

non-bolus forming materials, the urge to swallow was related to the hardness of the food. Here, more

chewing and thus fracturing into smaller fragments was required for firm compared to softer materials.

As fat is a main carrier of taste compounds, it is important to find out how its properties changes through

mastication. We found that the microstructure of the fat phase for a soft material as cheese remained

generally constant throughout the chewing cycle, i.e. the fat inclusions stayed separated within the protein

matrix and did not merge or break up into smaller entities. On the other hand, for a solid snack food

product (potato chips) the fat phase ended up being partly emulsified by the chewing action. The increased

surface area caused by the emulsification would possibly lead to a faster and/or increased sensory

detection of fat soluble taste and aroma compounds as well as having an impact on digestion rates.

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16

OP-2

Underlying mechanisms for sensory perception of double emulsions with gelled and non-gelled

w1 phase

Anika OPPERMANN1,2, Elke SCHOLTEN1, Markus STIEGER2 1 Physics and Physical Chemistry of Foods (Wageningen University, Wageningen, The Netherlands) 2 Division of Human Nutrition (Wageningen University, Wageningen, The Netherlands)

The use of double emulsions (w1/o/w2) has been acknowledged as a promising strategy to reduce oil

content in several food applications. In double emulsions, water droplets (w1) are included in oil droplets

(o) which are dispersed in another aqueous phase (w2). It is generally assumed that using double

emulsions, oil content can be reduced while maintaining sensory properties, especially perception of fat-

related attributes. However, while sensory perception of single emulsions (o/w2) has been studied

extensively, a study on fat-related sensory properties of double emulsions has not been reported yet.

In this study, we investigated the sensory perception of double emulsions by descriptive sensory

profiling using a trained panel. Double emulsions varying in composition (gelled and non-gelled inner w1

phase) and fat reduction level were evaluated on attributes describing the taste (T), mouthfeel (MF) and

after-feel (AF) perception, including thickness (MF), creaminess (MF, AF), fattiness (MF, AF), and

cohesiveness (MF). Single emulsions (o/w2) with the same dispersed phase fraction (oil) were used as

references. Oil droplet sizes and viscosities of the emulsions were similar to minimize the effect of those

properties on sensory perception.

We found that the replacement of oil with small water droplets w1 did not decrease perception of

fat-related attributes, and even increased when inner droplets were gelled. This indicates that the sensory

perception of single and double emulsions is mainly determined by the total droplet surface area. The

sensory properties are correlated to the lubrication properties of the emulsions as a function of the

composition and amount of inner water phase. This study shows that fat reduction of up to 45% can be

achieved using double emulsions while maintaining or enhancing perception of fat-related attributes. This

insight confirms the potential of double emulsions as oil replacers.

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17

OP-3

The structure of dairy products effects gastrointestinal digestion at multiple length-scales

Alan MACKIE1, Anabel MULET-CABERO1, Neil RIGBY1, Simon LOVEDAY2, Janiene GILLILAND2, Maria FERRUA2 1 Institute of Food Research, Norwich, UK 2 The Riddet Institute, Palmerston North, New Zealand)

Using a semi-dynamic in vitro simulation and gastric emptying rates determined in vivo1, we describe a

comparison of the digestion of a liquid in which the lipid is in the form of an emulsion and semi-solid dairy

based food, where much of the lipid is embedded in a protein matrix. Both foods contained the same

amount of protein and lipid. The changes in gastric pH as a function of time indicated that the different

structures led to differences in buffering capacity. However, this was complicated by the emptying profiles

of both the protein and lipid from the two meals. Analysis of the lipid droplet size showed very little change

in the gastric phase but the differences in large-scale structure led to differences in the timing of lipid

digestion.

In addition to comparing the two food systems we also studied the effect of physical processing by

digesting the same foods in a simple minimally stirred simulation and the “human gastric simulator” (HGS)

published previously2 that more closely mimics the peristaltic action of the stomach. For these two foods,

the results were remarkable similar, suggesting that accurate simulation of physical processing may only be

important for solid meals.

The analysis of lipid and protein hydrolysis is interpreted in the light of in vivo data previously published

and confirms that the food structure tailored to alter physiological response.

1. Mackie, A. R., Rafiee, H., Malcolm, P., Salt, L. & van Aken, G. (2013). Specific food structures supress appetite

through reduced gastric emptying rate. American Journal of Physiology - Gut and Liver Physiology, 304(11), G1038-

G1043

2. Kong, F. B. & Singh, R. P. (2010). A Human Gastric Simulator (HGS) to Study Food Digestion in Human Stomach.

Journal of Food Science, 75(9), E627-E635

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18

OP-4

Flavour Release during Food Processing: a Taste of Mass Transfer

Martijn WETERINGS1,2, Igor BODNAR3, Remko M. BOOM2, Michael BEYRER1

1 HESSO Valais-Wallis Institute of Life Technologies, Sion, Switzerland 2 WU Agrotechnology & Food Sciences, Wageningen, Netherlands 3 Firmenich S.A., Geneva, Switzerland

Flavours in foods are meant to be released just before and during consumption of the product. However,

already during preparation of the foods, some of the flavours are released and lost for the product. This

does not just imply a loss of flavour, but will also influence the overall flavour balance at the moment that

the food is consumed.

A quantitative understanding of flavour release during processing allows the compensation for the losses

such, that the product during consumption will have just the right flavour balance, while the understanding

of the mechanisms will allow the reduction and perhaps even elimination of flavour losses during

processing.

An experimental laboratory scale setup was developed that mimics the steps in food processing and

simultaneously allows in-line measurement of the flavour concentrations in the aroma head space. With

this we can quantify changes in flavour release as function of both product and process parameters.

We observe reduced release of aroma for smaller stirring velocities and food matrices with larger

viscosities. These effects are less pronounced at lower temperatures and for molecules with higher Henry’s

coefficients.

These results are combined with a mass transfer model that captures all relevant transfer phenomena in

this multiphase system. The aroma release is greatly affected by the mass transport processes and varies

depending on the experimental settings. Using dimensionless parameters we sketch a description of the

changes in flavour concentrations during processing.

A connection is made to the consequences for the flavour balance and perception during oral consumption.

Mass transfer is not often a focus in the multidisciplinary, complex, experimental research on oral

consumption, yet it may be a vital part of the answer to many questions: Why and how does temperature

influence perception of the aroma of a wine? What makes the perception of aroma different during nosing,

swirling and aftertaste? Why is there such a variety in conclusions about the role of viscosity on aroma

release in the mouth? Here we will use the fundamentals of mass transfer as described above to guide the

answers on the sensory questions.

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19

OP-5

Tribological and sensory properties of food particles in liquid and semi-solid foods

Kun LIU 1, 2, Markus STIEGER 1, 2, Erik VAN DER LINDEN 1, 2, Fred VAN DE VELDE 1,3 1 TI Food & Nutrition, Wageningen, The Netherlands 2 Wageningen University, Wageningen, The Netherlands 3 NIZO Food Research, Ede, The Netherlands

The application of tribology in food research has revealed important relationships between lubrication properties and perception of fat-related sensory attributes of foods. We investigated the tribological and sensory properties of two micro-particle fat replacers (microparticulated whey protein (MWP) and rice starch), and fat droplets differing in solid fat content (SFC) and interaction of fat droplets with the gel matrix (bound/unbound) in liquid and semi-solid model foods. Fat droplets embedded in semi-solid gels reduced friction due to formation of fat films following a plate-out mechanism. The formation of fat films was enhanced by 1) increasing the amount of fat; 2) releasing unbound fat droplets from the gel matrix and 3) coalescence of fat droplets due to high SFC. Emulsifiers influenced the friction through formation of emulsifier films. Sensory results (QDA) showed that both 1) and 2) were able to increase the perception of fat-related sensory attributes, whereas 3), high SFC had no significant effect, probably due to in-mouth melting of the fat and structure breakdown. Spherical MWP particles effectively reduced friction in both liquid and semi-solid matrices due to a ball-bearing lubrication mechanism. Ball-bearing lubrication was restricted by gel matrices. Sensory results (QDA) revealed that MWP did not contribute to the perception of fat-related sensory attributes as fat droplets did, which could be related to their different lubrication mechanisms. In liquids, small MWP particles contributed to creaminess perception maybe due to ball-bearing lubrication while larger MWP particles contributed to roughness perception, which was negative on creaminess perception. Irregular-shaped native and gelatinized rice starch particles increased friction due to 3-body abrasion. Therefore, the fat-mimicking functionality of rice starch might be mainly due to increasing bulk viscosity or saliva-relevant effect. We conclude that the morphology of food particles in liquid and semi-solid foods influences the mechanisms underlying the lubrication properties that can influence sensory perception.

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20

Biopolymer Assembly

KEY-BA

Ethylcellulose interactions with colloidal particles and its effect on structuring jammed systems

Alejandro G. MARANGONI, Terri A. STORTZ

University of Guelph, Guelph, Canada

Recent work by our group has shown that sucrose crystals have the ability to interact with ethylcellulose (EC) and form a network within food materials that provides mechanical strength and thermal stability. We recently reported on the ability of EC to impart heat resistance in chocolate using a solvent-substitution (SS) method. In the SS method, EC dissolved in ethanol is incorporated into a food matrix. Upon removal of the ethanol by evaporation, the EC will interact with different structures within the matrix. Evidence suggests that the sucrose present in the chocolate plays a major role in the heat resistance. Here we show that EC is able to hydrogen bond with sucrose which allows for the creation of an oil-trapping network. Atomic scale molecular dynamics simulations and FTIR spectroscopy both showed the ability of EC to hydrogen bond with sucrose. Large deformation mechanical testing and scanning electron microscopy showed the ability of EC and sucrose to form a network within an oil medium which resisted deformation. Here we also show that the presence of lecithin at the surface of sucrose reduced heat resistance by impeding interactions between EC and sucrose. These techniques along with fluorescence microscopy also showed that the ethanol used in the SS method was able to remove the ethanol- soluble lecithin phospholipids from the surface of the sucrose. Removal of the lecithin and the slight solubility of sucrose in ethanol both have positive impacts on heat resistance. It was also found that ethanol can reduce heat resistance by destabilizing the casein micelle in samples made with skim milk powder. Finally, results have indicated that EC is likely able to interact with the lactose in skim milk powder and the starch in cocoa powder leading to greater heat resistance. These results have led to an understanding of the mechanism of heat resistance in EC solvent substitution chocolate and will be useful in developing new food products containing EC as a functional ingredient that enhances sugar networks. Furthermore, there is evidence that a strong, heat resistant network can be created for various particles other than sucrose including glucose, starch, and even diamond dust.

Stortz, T. and Marangoni, A.G. 2011. Heat Resistant Chocolate. Trends in Food Science and Technology 22: 201-214. Stortz, T.A. and Marangoni, A.G. 2013. Ethylcellulose Solvent Substitution Method of Preparing Heat Resistant Chocolate. Food Research International 51: 797-803. Stortz, T.A., Laredo, T. and Marangoni, A.G. 2014. Molecular interactions of sucrose and ethylcellulose. RSC Adavances 4: 55048-55061. Stortz, T.A., Laredo, T. and Marangoni, A.G. 2015. The role of lecithin and solvent addition in ethylcellulose-stabilized heat resistant chocolate. Food Biophysics 10: 253-263.

Ethylcellulose and ethanol induced aggregation

sugar particles within a chocolate sample

responsible for the heat resistance of chocolate.

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21

BA-1

Hybrid oleogel made of polymer and crystalline gelators

Maya DAVIDOVICH-PINHAS1, Andrew GRAVELLE2, Shai BARBUT2, Alejandro MARANGONI2 1 Technion – Israel Institute for Technology, Haifa, Israel 2 University of Guelph, Guelph, Canada

Oleogel formulations have been studied extensively over the last few years for various applications.

Oleogels can be classified into two major groups depending on the gelator component used, low and high

molecular weight oleogelators (LMOGs and HMOG). The physical properties of LMOG based gel systems are

strongly affected by geometric properties of the primary structurant, such as surface area and volume,

which, in turn, are directly affected by cooling rates and shearing. HMOG based gels, on the other hand,

offer different properties for possible applications, the consequence of extended polymeric chains. The

current research aims to combine both strategies to form a hybrid oleogel system which benefits from both

worlds. Oleogel system with 6 %Wt ethyl-cellulose (EC) and 3% or 5% Wt steryl alcohol /stearic acid 7:3

ratio (SOSA) was formulated and investigated using mechanical, thermal, and structural analysis. Sol-gel

transition was investigated using rheological approach. Reduction in the sol-gel cross-over temperature was

observed with the increase in SOSA concentration suggesting a plasticizing effect of the SOSA molecules.

The melting/crystallization transitions of the SOSA was evaluated using differential scanning calorimetry

(DSC). Shift in the SOSA crystallization peak to higher temperatures was observed in the presence of EC.

This observation was related to possible interactions between the polymer and the SOSA leading to the

formation of nucleation points which promote crystal growth. Unique crystal feather-like organization was

observed by optical microscopy imaging for EC/SOAS/oil mixture compare to SOSA/oil needle-like crystals.

X-ray diffraction analysis verified the existence of β and β' polymorphs in the SOSA crystal. These

polymorph structures were maintained after EC addition implying on the formation of two individual

networks, the polymer EC network and the SOSA crystal network. According to the DSC and imaging results,

it seems that these two networks are connected. Mechanical analysis also revealed a synergistic

enhancement in the final gel strength, possibly due to interactions between the SOSA and EC during

gelation. This research provide a first investigation of hybrid system using two different oleogelation

techniques. Such systems can benefit from synergistic effects, which can potentially offer enhanced

systems with unique array of characteristics.

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22

BA-2

Protein aggregates as building blocks for oil structuring

Auke DE VRIES1,2, Erik VAN DER LINDEN1, Elke SCHOLTEN1,2 1 Top Institute Food and Nutrition, Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands. 2 Wageningen University, Physics and Physical Chemistry of Foods, Bornse Weilanden 9, 6708 WG

Wageningen, The Netherlands.

Over the recent years, structuring of oil into organogels or oleogels has gained much attention from colloid,

material and food scientists. An oleogel can be defined as an organic liquid with low polarity, entrapped

into a three-dimensional network. Such oleogels could potentially be used as an alternative for saturated-

and trans fats within the food industry. Besides chemically synthesized molecules, many biocompatible

organo- and oleogelators have been identified and characterized over the last years and can be classified as

either low molecular weight or polymeric organogelators. For food applications, it is of importance to

identify oleogelators that are sustainable, cost effective, and biocompatible. Therefore, there is still a great

need to identify food-grade biopolymers that are able to gelate a common oil.

Proteins are one of nature’s greatest resources of biopolymers and their gelation of water is well known.

Due to their hydrophilic character, however, their use as oleogelator is limited. In this presentation, we will

show that whey proteins can be used as a structuring agent for oil gelation. To this end, first, heat-set

protein gels or protein aggregates are created in an aqueous environment. Then, the continuous aqueous

phase is exchanged for a continuous liquid oil phase via an intermediate solvent. We show that by using

this procedure, the resulting protein matrix is capable of binding a large amount of liquid oil without any

necessary protein modification.

The use of protein aggregates as building blocks for organogelation shows interesting versatility. Different

protein networks can be formed since the properties of the building blocks and their interactions can be

controlled. This allows in turn to control rheological properties, such as gel strength, yield stress and plastic

behavior. Our results show that whey proteins can act as a cheap and versatile oil structuring biopolymer.

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23

BA-3

Casein micro-particle as carriers for hydrophobic substances - a new approach for its isolation

and characterization

Yu ZHUANG1, Julia STERR2, Alica SCHULTE1, Ulrich KULOZIK3, Ronald GEBHARDT1* 1 Chair of Food Process Engineering and Dairy Technology, Technische Universität München, 85354,

Freising-Weihenstephan, Germany 2 Chair of Food Packaging Technology, Technische Universität München, 85354, Freising, Germany 3 Institute for Food and Health (ZIEL) – Technology Unit, Technische Universität München, 85354, Freising-

Weihenstephan, Germany

Micro-particles received abundant attentions from food research because of their potential use as carriers

for bioactive substances. In this talk, we report on a new method to form casein micro-particles using

casein/pectin blend films. The underlying mechanisms for the micro-particle formation are depletion forces

due to volume exclusion. Confocal Raman microscopy, liquid chromatography and IR spectroscopy were

applied to characterize their composition and microstructure in both blend film and liquid phase. Raman

images showed incompatibility between both polymers because particles consisted of casein and the

surrounding matrix of pectin only. Deformation of micro-particles into an oblate shape took place during

film formation indicating a compaction of the structures. After isolation by enzymatic hydrolysis, micro-

particle remained stable in solution. Their size ranged from 10 to 50 µm similar to those in films. IR and

Raman spectra indicated that micro-particle mainly consisted of caseins. Furthermore, compared to the

composition of native caseins, an increased amount of α-S2 casein was found in the micro-particles. To give

them functionality, casein micro-particles were loaded with α-tocopherol. The porous structure of the

micro-particles supported the inclusion of α-tocopherol. Their linkage to the casein matrix within the

particles will be discussed in detail. Our approach demonstrates a new route to form micro-particles with

bio-functionality which might play a future role in the design of functional foods.

Fig. Color-coded Raman microscopic image in blend film in (A) vertical and (B) horizontal direction, casein-rich region, and pectin-rich (green). References: Maroziene, A.; de Kruif, C. G (2000): Interaction of pectin and casein micelles. In Food Hydrocolloids.Zhuang, Y; Sterr, J; Kulozik, U; Gebhardt, R (2015): Application of confocal Raman microscopy to investigate casein micro-particles in blend casein/pectin films. In International Journal of Biological Macromolecules.

Food Colloids 2016

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24

BA-4

pH-dependent Self-assembly of Native Soy Globulin in Aqueous Solution and Heat Induced

Aggregation

Nannan CHEN1, 2, Mouming ZHAO2, Christophe CHASSENIEUX1, Taco NICOLAI 1 1 LUNAM Université du Maine, IMMM UMR-CNRS 6283, Polymères, Colloïdes et Interfaces, 72085 Le Mans

cedex 9, France 2 College of Light Industry and Food Sciences, South China University of Technology, 510640, Guangzhou,

China

Soy globulin is a mixture of proteins with two main components glycinin and β-conglycinin. As an important

food ingredient, it has been used and studied for a long time. However, the state of native soy globulin in

aqueous solution and the heat-induced aggregation is still not fully understood. Most of the former studies

were rather limited in scope and the combined effects of concentration, pH and temperature on the

aggregation have not been investigated. Here, we use both light scattering and rheology to understand the

aggregation behaviour of soy globulin in a wide range of concentration (0.1-100g/l) and pH (pH 5.8-7.1) in

salt free solution both at room temperature and while heating at various temperatures. Results indicated

that native soy globulin self-assembled into self-similar aggregates with sizes that increased with increasing

concentration. Aggregates formed at higher concentrations dissociated over a period of days when the

solutions were diluted. The extent of self-assembly increased with decreasing pH and was determined by

the charge density of the proteins. When the soy globulin solutions were heated, irreversibly cross-linked

self-similar aggregates were formed with sizes that increased with increasing concentration until above a

critical concentration the system gelled. The kinetics of this process was investigated systematically as a

function of the temperature and the protein concentration.

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25

BA-5

Production & Use of Protein or Polysaccharide Microgel Particles via Jet Homogenization

Brent MURRAY1, Linda PRAVINATA1, Nataricha PHISARNCHANANAN1, Kentaro MATSUMIYA2 1 University of Leeds, Leeds, UK 2 Kyoto University, Kyoto, Japan

Food microgel particles, down to particle sizes of ca. 100 nm, have been produced via a very simple

technique of rapid and highly turbulent mixing of biopolymers: (a) during their gelation or (b) post

formation of coarse gel particles, by forcing the material to pass through a Jet Homogenizer previously

developed for preparation of oil-water emulsions. Microgel particles of alginates, carageenans and pectins

have been produced by so mixing together separate streams of the biopolymer solution and a solution of

CaCl2. The final mean particle size depended mainly on the relative concentration of biopolymer and Ca2+

and to a lesser extent the homogenization pressure (above a minimum pressure of ca. 150 bar) or the

relative volumes of the biopolymer and CaCl2 solutions. The smallest particles were obtained for the most

calcium sensitive biopolymer: alginate; larger p

-carageenan. The ability to trap both soluble and insoluble food ingredients within these

particles during their formation was demonstrated with food colours (e.g., erioglaucine) and flavonoids

(e.g., rutin and tiliroside) and curcumin, respectively. Some reduction in alginate microgel particle size and

-potential was obtained by including lactoferrin during particle formation, presumably due to

accumulation at the surface of the (negative) calcium alginate particles by at least some of the oppositely

(positively) charged lactoferrin, which effectively acts as a surfactant for the system.

Protein microgel particles were formed from whey protein isolate (WPI) or soy protein isolate (SPI) by

thermal gelation of protein in the bulk, breaking the gels into coarse fragments and then passing them

through the Jet Homogenizer up to 3 times. The WPI microgel particles were demonstrated as very

effective Pickering stabilizers of both oil-in-water (O/W) and water-in-water (W/W) emulsions. Sunflower

O/W emulsions were significantly resistant to in vitro lipid digestion after further heat processing, by

enhancing particle aggregation at the O-W interface. Phase separation of a waxy corn starch + locust bean

gum system was significantly inhibited, again particularly on inducing particle aggregation at the W/W

interface, this time via acidification to near the protein pI. The SPI microgel particles showed enhanced

foam stabilizing properties compared to suspensions of the non- gelatinized SPI and enhanced stability of

O/W emulsions to freeze-thaw. All microgel particle sizes (protein or polysaccharide) on exiting the Jet

Homogenizer could be slightly reduced further via sonication, indicating that they were initially aggregated

to some extent.

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26

BA-6

Delivery of functional ingredients by self-assembled modified food biomacromolecules

Yuan LI1, Wei LI1, Luhai ZHAO1, Mengxuan SHI1, Willem NORDE2 1 College of Life Science and Technology (Beijing University of Chemical Technology,Beijing, China) 2 Laboratory of Physical Chemistry and Soft Matter (Wageningen University, Wageningen, The Netherlands)

The natural bioactive ingredients are usually sensitive to the environmental stimuli such as acid, heat, light and oxygen. It is important to develop an effective strategy to protect them from early degradation. Moreover, delivering them to the specific sites such as small intestine can increase their bioavailability. Biopolymers based on food grade materials are desirable in food application due to its biocompatibility and biodegradability. Here β-carotene is used as the model for hydrophobic bioactives, and the anthocyanin is used as the model for hydrophilic bioactives. We have developed a microsphere multi-nutrients delivery system based on cross-linked oxidized polysaccharides – oxidized Konjac Glucomannan1-5. Those microspheres are capable of encapsulating the hydrophilic and hydrophobic compounds simultaneously, and delivering them into intestine for targeted absorption (Fig.1). Secondly, we also developed a structurally well-controlled amphiphilic peptides obtained by enzymatically hydrolysed whey protein. This amphiphilic peptide has a well-defined structure, which can self-assemble into nanotubes and micelles at different conditions. β-carotene can be incorporated into the whey protein micelles via hydrophobic interaction, and the staining dye (representing anthocyanin) can be absorbed into whey protein nanotubes cavity through electrostatic interaction. Those modified polysaccharides and protein delivery system opened new option for encapsulating bioactives, which may facilitate their application in all kinds of foods, and improve their nutritional and health value in functional foods.

References : 1Langmuir,28,1545-1551,2012 ;

2Biomacromolecules,15,2166-2171,2014 ;

3 Food Hydrocolloids, 51, 476-485, 2015 ;

4Colloids and Surfaces B :Biointerfaces,127,96-104,2015 ;

5JAFC,63,8669-8675,2015.

Fig.1.CLSM images of anthocyanins absorbed

polymer phase(left) and β-carotene contained

oil phase(Middle)and the overlay of the two

phases. The multi-nutrients delivery microspheres made by double emulsion method.

Fig. 2.(A)Unstained and stained protein

nanotubes.(B) β-carotene poorly dissovle

in water and β-carotene encapsulated by

protein micelles.

Food Colloids 2016

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27

BA-7

Formation of fibrous protein structures from a condensed water-in-water emulsion by simple

shear flow deformation

Birgit DEKKERS, Costas NIKIFORIDIS, Remko BOOM, Atze Jan VAN DER GOOT

Food Process Engineering, Wageningen UR, Wageningen, the Netherlands

Mixtures of two thermodynamically incompatible biopolymers lead to the formation of water-in-water

(w/w) emulsions. When simple shear flow is applied on such w/w emulsions in a condensed state,

anisotropic macrostructures with a fibrous appearance can be formed. Shear-induced structuring of plant

based polymer blends is of high interest, since it can lead to novel applications in material and food science,

like meat alternatives. Food raw materials or fractions thereof contain those biopolymer blends naturally.

We research shear-induced structure formation of a condensed phase separated pectin/soy protein blend

because these two biopolymers, are naturally present in soy protein concentrate. Application of simple

shear flow on this pectin/soy protein blend lead to anisotropy and fibrous materials. Scanning Electron

Microscope analysis revealed that shear-induced structuring resulted in elongated pectin filaments,

oriented in the direction of the shear flow. These filaments are entrapped in a continuous protein matrix.

The length of these pectin filaments was shown to play a key role in the degree of anisotropy as measured

with the tensile strength analysis. The tensile strength was dependent on the phase arrangement of the

biopolymers. The length of pectin filaments was dependent on heating temperature (120-140oC) and pectin

concentration (1.3-4.0 wt%). Largest pectin droplets, and hence strongest anisotropy, were found for

samples heated at 140oC and consisted of 2.2 wt% pectin in SPI. This work contributed to a better

understanding of fibrous structure formation from condensed w/w emulsions. Besides, we have a better

understanding of the role and importance of pectin and soy protein in shear-induced structure formation,

which enables a better design of functional fractionation processes.

Food Colloids 2016

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28

BA-8

Smart delivery vehicles based on the self-assembled complexes of the food biopolymers with

polyunsaturated lipids stabilized by plant antioxidants: structure-functionality relationships

Maria G. SEMENOVA1, Anna S. ANTIPOVA1, Natalia S. VOROBYEVA1, Natalia V. SMOTROVA2, Vera

A. SENINA3, Nadezda P. PALMINA1, Tamara A. MISHARINA1, Ekaterina S. ALINKINA1, Vladimir I.

BINYUKOV1, Natalia G. BOGDANOVA1, Valerii V. KASPAROV1 1 N. M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Kosygin str. 4, 119334

Moscow, Russian Federation 2 D. I. Mendeleyev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, Russian

Federation 3 M. V. Lomonosov Moscow State University, Leninsky hills, 1, 119991 Moscow, Russian Federation

There is a considerable current interest in the elaboration of both the protective and the controlled–release

delivery vehicles for the wide variety of nutraceuticals, which could be used as the health-promoting food

ingredients, in particular under the functional food formulation. The polyunsaturated fatty acids (PUFAs),

especially omega-3 and omega-6 are the most important nutraceuticals. However, there are the real

challenges of using the PUFAs in the functional low- fat food elaboration. The first and most important one

is their high susceptibility to an oxidative degradation during the food product preparation, transport, and

storage, and the second one is their low solubility in water and in biological liquids in a body that can

decrease their bioavailabilty. In order to solve these problems we have tried to use, on the one hand, the

expected high both encapsulation ability and solubility in an aqueous medium of such biopolymer

amphiphilic particles like sodium caseinate and covalent conjugate (sodium caseinate (SC) + maltodextrin

(MD-SA2)), produced by the Mailllard reaction, and, on the other hand, the effective plant antioxidants as

either an ether oil of clove or oleoresins of ginger. As the main lipid objects of our investigation we have

chosen different mutually complementary combinations of the polyunsaturated lipids, which can provide

the equimass omega-6/omega-3 PUFAs ratio : the equimass mixture of -linolenic (ALA) and linoleic (LA),

the mixtures of the the soy phosphatidylcholine (PC) liposomes enriched in LA with both ALA and

docosahexaenoic DHA, the soy lysophosphatidylcholine (LPC) LPC micelles enriched in LA with both ALA

and DHA. In such a manner in our work we have tried to get a more deep insight into the structure –

functionality relationships for the supramolecular complex particles formed.

As the functional properties of the complex particles we have considered both their protective abilities

against oxidation of the lipids, their solubility in an aqueous medium and their abilities to the controlled

release of the lipids in the simulated gastro-intestinal tract in vitro.

With this object in view we have used a combination of such basic physico-chemical methods as the

spectrophotometry, the static and dynamic multiangle laser light scattering, the particle electrophoresis,

the atomic-force microscopy, and the electron spin resonance spectroscopy.

Acknowledgements: Authors are most grateful to the Russian Science Foundation for the financial support

of this study (Grant № 14-16-00102).

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BA-9

Oleosome Based Gels Prepared by Hydrocolloid Trapping

Behic MERT1, Thomas A. VILGIS2 1 Food Engineering Department Middle East Technical University, Ankara Turkey 2 Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Lipids are in general preserved in the form of triacylglycerols (TAG) in seeds and plants. These TAGs are

segregated into nano to micrometer spherical bodies. These spherical oil bodies, also called oleosomes,

possess unique surface properties as they must stabilize water-insoluble TAGs in a hydrophilic

environment. When oleosomes are extracted from seeds or plants they are in the form of concentrated

emulsions with their natural emulsifier oleosins. In this study oleosome based oleogels were developed by

trapping oleosomes in a hydrocolloid matrix. Physical trapping of oleosomes were accomplished through

electrodeposition procedure consisting of coating negatively charged oleosomes with a positively charged

hydrocolloid at low pH values. Stabilized oleosome emulsions were further stabilized by removal of water

through drying, then the resulting dry structures were sheared using a high speed mixer and oleogels were

obtained. Final oleogels contained mainly oil and minor amounts hydrocolloids and storage proteins.

Rheological studies conducted on the oleogels samples revealed that oleogels had solid like structures and

low degree of thixotropic behavior. As an application of the oleosome based oleogels hazelnut oleogels

were mixed with cocoa and extra fine sugar to obtain saturated fat and palm free spreads.

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Revealing Structure from Micro to Macro

KEY-RS

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RS-1

Extended Colloidal Networks in Emulsions. 3-D imaging by Ptychographic X-ray computed

tomography

Jens RISBO1, Mikkel Schou NIELSEN2, Merete BOGELUND MUNK1, Ana DIAZ3, Emil Bøje LIND4

PEDERSEN, Mirko HOLLER3, Stefan BRUNS5, Kell MORTENSEN2, Robert FEIDENHANS’l2

1 Department of Food Science, University of Copenhagen, Rolighedsvej 30, 2000 Frederiksberg, Denmark 2 Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark 3 Paul Scherrer Institute, 5232 Villigen – PSI, Switzerland 4 Department of Energy Conversion, Technical University of Denmark, Frederiksborgvej 399, 4000

Roskilde, Denmark 5 Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark

Colloidal networks in food and food materials like cheese, yoghurt, whipped cream and fat is decisive for

the texture and mouthfeel. The ability to image by optical means and thereby obtain knowledge structure

is often limited by the high degree of light scattering and so far only few 3D structures has been obtained of

such networks. We have made use of synchrotron x-ray radiation to perform the non-destructive 3D

imaging technique ptychographic X-ray computed tomography (PXCT) [1] and obtained a 3D electron

density map of partially coalesced samples of whippaple O/W emulsions with a resolution 300 nm. The

resolved electron density values are within 4% of reference values of the components of the emulsion. The

study revealed network formation where about 98% of the fat particles was a part of the same network

structure. Analysis using a watershed algorithm highlighted how the structure was constructed from

colloidal elements with a size distribution close to the one of the original emulsion sample. A 3D printed

plastic model of the colloidal network was produced to along with computer based 2D visualization.

Altogether, PXCT is a promising tool for spatial and quantitative investigation of food products on the sub-

micron scale.

[1] M. Dierolf, A. Menzel, P. Thibault, P. Schneider, C. M. Kewish, R. Wepf, O. Bunk, F. Pfeiffer, Ptychographic x-ray

computed tomography at the nanoscale, Nature 467 (7314) (2010) 436–439.

Figure 1. 3D colloidal network in emulsions system

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RS-2

Structure of soybean oleosomes studied by small angle neutron scattering (SANS)

Birgitta I. ZIELBAUER1, Sania MAURER1, Gustav WASCHATKO1, Andrew J. JACKSON2,3, Marta

GHEBREMEDHIN1, Richard K. HEENAN4, Lionel PORCAR5, Thomas A. VILGIS1 1 Max Planck Institute for Polymer Research, Mainz, Germany 2 European Spallation Source, Lund, Sweden 3 Lund University, Lund, Sweden 4 ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, United Kingdom 5 Institut-Laue-Langevin, Grenoble, France

In oleaginous plants such as oil seeds or nuts, fat is stored in oil bodies, also called oleosomes. Their size is depending on the plant species and ranges from several hundred nanometers (soybeans) up to a few micrometers (cocoa). These colloidal particles are composed of a lipid core, stabilized by a monolayer of phospholipids and proteins. These proteins play a crucial role for the stability of the droplets. The most abundant of them, the so-called oleosins, contain one of the longest hydrophobic domains known in nature, anchoring them deep inside the oil core (Fig. 1). Their terminal ends are orientated towards the aqueous environment and keep the droplets apart from each other through steric hindrance and electrostatic repulsion.

Fig. 1: Schematic view of an oleosome.

Oleosomes can be extracted by aqueous processes yielding highly stable emulsions and thus bear a high potential to be employed in various food and cosmetic systems. However, those applications may involve harsh environmental conditions such as shearing or temperature treatment, so it is important to know the oleosomes’ stability limits. Studying the native structure of oleosins is extremely difficult due to their long hydrophobic domain, causing aggregation upon extraction. Also, the exact conformation of the hydrophilic domains, as well as changes therein that may result from varying environmental conditions, are still a matter of debate [1]. Small angle neutron scattering is a non-destructive method that allows studying the outer shell of the oleosome in its native state. Soybean oleosomes are studied here due to their extraordinary stability. We employ the contrast variation method to obtain information about the size of the oleosomes as well as the thickness of the layer surrounding their lipid core and thus the protein conformation, in different environmental conditions. No change was found for heat treatments up to 80 °C, indicating the enormous heat stability of these oil bodies. [1] S. Maurer, G. Waschatko, D. Schach, B. I. Zielbauer, J. Dahl, T. Weidner, M. Bonn, T. A. Vilgis, The role of intact oleosin for the stabilization and function of oleosomes, The Journal of Physical Chemistry B, 117 (2013), 13872-13883

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RS-3

Dynamic interfacial tension of emulsions studied with microfluidics

Kelly MUIJLWIJK1, Claire BERTON-CARABIN1, Karin SCHROËN1, 1 Food Process Engineering group, Wageningen University, Wageningen, The Netherlands

Many food products are emulsion-based systems, and generally they are made using high shear devices that induce fast droplet break-up (i.e., in the millisecond range) in the presence of emulsifiers. It is expected that emulsifier adsorption occurs at similar time scales as droplet breakup during emulsification; it is therefore crucial to understand the early steps of emulsion droplet formation and emulsifier adsorption. However, conventional tensiometry techniques are not able to measure changes in interfacial tension related to emulsifier adsorption at such small time scales. A device that can enable the measurement of interfacial tension in the millisecond range is the microfluidic Y-junction (Figure 1, left), which is the focus of the present work. Here, the droplet size depends on the shear of the continuous phase, and on the interfacial tension. A reduction in the interfacial tension, as a result of emulsifier adsorption, leads to the formation of smaller droplets. Based on the droplet size and flow rates, the interfacial tension at the moment of droplet break-up, also called dynamic interfacial tension, can be measured in the millisecond range. We constructed a model that relates the droplet size to the shear exerted by the continuous phase, and to the interfacial tension. With this model, the interfacial tension at the moment of droplet formation (typically between 0.5-10 milliseconds) could be calculated. The emulsifier coverage of the oil droplet depends on the process conditions, leading to different values of the dynamic interfacial tension at the moment of droplet break-up, and we were able to link this to droplet formation time and emulsifier concentration (Figure 1, right). The proposed method allows exploration of emulsifier behaviour at the oil-water interface at very short time scales, which is not possible through any other technique. It is expected that this information will help the food industry to optimise their ingredient formulation and processing conditions, using adsorption behaviour as a starting point of their product and process designs.

Figure 1. Oil droplet formation in a Y-junction microfluidic device (left), and dynamic interfacial tension of 0.01 (●), 0.1 (♦) and 0.5 (▲)wt. % SDS as a function of the droplet formation time (right).

0

10

20

30

40

50

0 2 4 6 8 10

γ d (m

N/m

)

tdrop (ms)

No coverage

Full coverage

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RS-4

Milk protein hydrolysis during in-vivo and in-vitro digestion:

Peptide generation and degradation

L. EGGER1, H. STOFFERS1, P. SCHLEGEL2, D.GUGGISBERG1, P. STOLL2, G. VERGERES1, R. PORTMANN1 1 Agroscope Institute for Food Sciences, Schwarzenburgstr. 161, 3003 Bern, Switzerland 2 Agroscope Institute for Livestock Sciences, Tioleyre 4, 1725 Posieux, Switzerland

The digestion processes are the interface between food and bioavailability of nutrients and understanding

the molecular mechanisms is a prerequisite to develop food with improved properties. During the digestion

process, protein hydrolysis and subsequent generation of peptides and free amino acids depend on the

structure and sequence of each protein. During the gastric phase, proteins are denatured in the acidic

conditions of the stomach and protein hydrolysis starts through the action of pepsin. At the intestinal stage

of digestion, proteases, such as trypsin, chymotrypsin, elastase and others, further degrade the proteins

and peptides until they are absorbed through the intestinal epithelium. Generation and destruction of

specific peptides during digestion of skim milk powder were investigated in vitro using the international

consensus COST Infogest digestion protocol and verified in vivo in a pig model. The hydrolysis of the five

most abundant milk proteins – their peptides and free amino acids – was investigated by mass

spectrometry and HPLC after the gastric and the intestinal compartment and compared between both

models. Moreover, with time-resolved in vitro digestion experiments, generation and degradation of

specific peptides and release of free amino acids were followed and compared with the in vivo pig data. The

protein specific hydrolysis was visualized by generation of abundance-dependent peptide patterns. Highly

abundant peptides observed after complete digestion indicate digestion-resistant protein sequences and

represent interesting sources of bioactive peptides or allergenic epitopes.

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RS-5

Passive Microrheologie as a useful tool for food analyses

Roland RAMSCH1, Maxime BAZIN1, Giovanni BRAMBILLA1, Mathias FLEURY1, Pascal BRU1, Gérard

MEUNIER1 1 Formulaction, 31240 L’Union, France

This work presents new applications using passive microrheology. Passive microrheology studies the

mobility and displacement of micron sized particles which results from Brownian motion [1]. The motion of

particles induces local deformations of the sample, which are directly related to its viscoelastic properties.

Our technique is based on Multi Speckle Diffusing Wave Spectroscopy (MS-DWS), which consists of

Dynamic Light Scattering (DLS) extended to an opaque media. With a patented algorithm, the

backscattered interfering light can be analysed in terms of Mean Square Displacement (MSD), which is

directly related to the viscoelastic properties of a sample. Moreover, the optical method allows to study

especially weak gels without any applied shear, which avoids perturbation of the sample.

Nowadays, cheese preparation has caught much attention, as it is a growing market. The milk properties,

such as pH, calcium content, protein content, are very important and change significantly the cheese

properties. This work shows how passive microrheology can be used to follow up the milk gel formation

with exact gel time determination. Gel time was determined by a new rescaling method, namely Time-Cure

Superposition (TCS) based on the Winter-Chambon criterion [2,3,4]. Moreover, the viscoelastic properties

of the preparation can be compared according to the parameters (protein enrichment). Results were

compared to other instruments (texturometers, rheometer, Optigraph®).

DWS combined with an accurate temperature control allows the study of the crystalline forms of fats and

waxes during melting and crystallization. This data is important for the elaboration of new products or for

quality control of finished products. In the case of chocolate, the microrheology analysis during melting can

identify the crystalline form of finished chocolate products, and help to predict its stability against

blooming.

[1] D. A. Weitz, D. J. Pine, in: Dynamic Light Scattering, W. Brown (Ed.) (Oxford Univ. Press, New York, 1993), Chap. 16

[2] T. H. Larsen, E. M. Furst, Phys. Rev. Letters, 2008, 100, 14600

[3] K. M. Schultz, E. M. Furst, Soft Matter, 2012, 8, 6198

[4] H. H. Winter, F. Chambon, J. Rheology 1986, 30, 364-382

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Functionality of Multicomponent Systems

KEY-MC

Molecular interactions, phase behavior and transport phenomena from a low-solid gel to a high-

solid glass

Stefan KASAPIS

School of Applied Sciences, RMIT University, Melbourne, Australia

Intelligent manipulation of the phase behaviour in biopolymer mixtures remains one of the basic tools of achieving the required structural properties and textural profile in novel food product formulations. As ever, the industrialist is faced with the challenge of innovation in an increasingly competitive market in terms of ingredient cost, product added-value, and long shelf-life to mention but a few. It appears, however, that a gap persists between fundamental knowledge and direct application to food related concepts with a growing need for scientific input. Furthermore, within the context of materials science, there is a tendency to examine research findings in either low- or high-solid systems without considering synergistic insights/benefits to contemporary needs, spanning the full range of relevant time-, temperature- and concentration scales. This review highlights the latest attempts made to utilize and further develop fundamental protocols in order to bridge the divide in the analysis from low to high-solid systems. Small and large deformation rheology, micro and modulated thermal analysis, and light/electron microscopy images constitute powerful tools in the characterization and quantification of such systems. Theoretical schools of thought from the

“sophisticated synthetic polymer” literature were adapted to address the specific requirements of research on structure/function relationships of biomaterials with changing solvent quality.1 Thus, the morphology of low-solid co-gels was explored using the isostress/isostrain blending laws, the Davis analytical expression, and the Lewis and Nielsen theoretical equations.2 In the high-solid counterparts, the combined free-volume/WLF framework was utilised to define the mechanical glass transition temperature that takes into account the presence of aqueous solvent in biomaterials.3 The coupling model of molecular dynamics identified the chemical moieties responsible for the local segmental motions at the vicinity of Tg.4 Understanding the molecular dynamics of biopolymers as glassy matrices allows monitoring the kinetics of diffusional mobility of entrapped bioactive compounds via a spectroscopic shift factor.5 Combining the physics of vitrification with Fickian kinetics of transport phenomena leads to the development of a mathematical expression that links the concept of micromolecular diffusion coefficient with the free volume of the polymeric matrix.6

1. Kasapis, S. & Tay, S.L. (2009). Morphology of molecular soy protein fractions in binary composite gels. Langmuir, 25, 8538 2. Shrinivas, P., Kasapis, S. & Tongdang, T. (2009). Morphology and mechanical properties of bicontinuous gels of

agarose and gelatin and the effect of added lipid phase. Langmuir, 25, 8763

3. Kasapis, S. (2006). Building on the WLF / free volume framework: Utilisation of the coupling model in the relaxation

dynamics of the gelatin / co-solute system. Biomacromolecules, 7, 1671

4. Kasapis, S., Al-Marhoobi, I.M., Deszczynski, M., Mitchell, J.R. & Abeysekera, R. (2003). Gelatin vs. polysaccharide in

mixture with sugar. Biomacromolecules, 4, 1142

5. Jiang, B. & Kasapis, S. (2011). Kinetics of a bioactive-compound (caffeine) mobility at the vicinity of the mechanical glass transition temperature induced by gelling polysaccharide. Journal of Agricultural and Food Chemistry, 59, 11825

6. Panyoyai, N., Bannikova, A., Small, D.M. & Kasapis, S. (2015). Diffusion kinetics of ascorbic acid in a glassy matrix of

high-methoxy pectin with polydextrose. Food Hydrocolloids, in press

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MC-1

Effects of disulfide bonding between added whey protein aggregates and other milk

components on the rheological properties of acidified milk model systems

Guanchen LIU1, Marianne LUND1, Colin RAY1, Søren NIELSEN2, Tanja JAEGER2, Richard IPSEN1 1 Department of Food Science, University of Copenhagen, Frederiksberg C, Denmark 2 Arla Foods Ingredients Group P/S, Videbæk, Denmark

Microparticulated whey protein (MWP) are colloidal particles usually formed by combined heating and

shearing of whey protein concentrates, typically having particle sizes ranging from 1.0 to 10 µm.

Nanoparticulated whey protein (NWP) is also produced from whey protein but having a smaller particle

size. In this research MWP and NWP were added to non-fat milk model systems and subjected to

laboratory scale homogenization (20 MPa) and heat treatment (90 °C 5 mins), and processed into

chemically acidified milk gels (glucono--lactone). The model systems contained 5% protein in total and

were made at two levels of casein (2.5% and 3.5% protein, w/w, based on micellar casein isolate powder)

with and without the thiol-blocking agent N-ethylmaleimide (NEM). Samples with added whey protein

ingredients were compared to four references: 5% (w/w) MWP, NWP or casein and a sample with 2.5%

(w/w) casein and 2.5% whey protein isolate (WPI) (w/w). The systems were characterized during processing

(homogenisation, heat treatment and acidification) by quantification of thiol groups, gel electrophoresis,

particle size, and rheology. The results showed that the formation of disulfide-linked structures in milk

model systems was closely related to the particle size and gels’ rheological behavior. The native whey

protein from WPI dominates the thiol/disulfide exchange reactions since not much native whey protein is

present in NWP and MWP. The systems with NWP exhibited obvious increase in particle size and higher

firmness of acidified gel through both covalent and non-covalent interactions. However, in MWP systems

the whey protein isolate (WPI) dominated formation of the protein network while MWP in itself resulted in

a weak protein network with low connectivity of the resulting gels. In addition, results show that

casein/whey protein ratio also plays an important role in aggregation during heating.

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38

MC-2

Effect of non-ionic emulsifier on structure and properties of a bench-scale model cheese

Seyed H. HOSSEINI-PARVAR1,2, Mita LAD2, Christina COKER2, Palatasa HAVEA2, Matt GOLDING1,2 1 Massey University, Palmerston North, New Zealand 2 Fonterra Research and Development Centre, Palmerston North, New Zealand

The use of W1/O/W2 double emulsion structures is considered a potentially useful technology for

replacement of fat in food applications. By using these emulsions, the amount of fat in a food formulation

can be decreased while maintaining the same amount of interface [1]. W1/O/W2 double emulsions are

often produced in a two-step method: first, the inner W1/O emulsion is produced and then this single

emulsion is emulsified in a second aqueous phase (W2) to obtain the double emulsion.

In this study, we investigated the incorporation of W1/O emulsions into a model cheese system, and

determined how the microstructure of this double emulsion system influenced cheese material and

functional properties. Initially, the stability of the water-in-oil (W1/O) emulsion prepared with milk fat was

determined as a function of emulsifier (polyglycerol polyricinoleic (PGPR)) concentration and water volume

fractions. Secondary emulsification took place when the stable W1/O emulsions were dispersed into fat-

free cheese through a mixing-cooking process (using a Rapid Visco Analyser) creating the final water-in-oil-

in-protein model cheese. The material properties and functionality of the cheese samples were evaluated

using small amplitude oscillatory shear test, particle size analysis, confocal laser scanning microscopy

(CLSM), cryo-SEM and modified Schreiber melt test.

The results demonstrate the ability of the secondary emulsification process to incorporate the W1/O

emulsion into the cheese matrix, providing a structure that has discrete fat domains (i.e. dispersed phase)

with internally filled water droplets. Increasing emulsifier concentration and water volume fraction had

minor effects on the fat structure within the cheese matrix.

Reference :

[1] Pawlik, A., Cox, P. W., & Norton, I. T. (2010). Food grade duplex emulsions designed and stabilised with different

osmotic pressures. Journal of Colloid and Interface Science, 352(1), 59-67.

Food Colloids 2016

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39

MC-3

The Effect of Competition for Calcium Ions on Heat-induced Aggregation and Gelation of

Mixtures of Whey Protein Isolate and Sodium Caseinate

Trong Bach NGUYEN1, Christophe CHASSENIEUX2, Christophe SCHMITT3, Lionel BOVETTO3, Taco

NICOLAI2 1 Faculty of Food Technology -Nha Trang university, Nha Trang, Vietnam 2 IMMM UMR CNRS 6283-Université du Maine, Le Mans, France 3 Department of Food Science and Technology-Nestlé Research Center, Lausanne, Switzerland

Whey proteins and caseins are the major protein components of milk. Heat-induced aggregation and

gelation of whey proteins is very sensitive to the presence of calcium ions that is the most often present in

the food products. Here we present an investigation of the effect of adding CaCl2 on the heat-induced

aggregation and gelation of Whey Protein Isolate (WPI) in the presence of sodium caseinate (NaCas) using

dynamic light scattering, confocal laser scanning microscopy (CLSM) and oscillatory shear rheology. We will

show that at neutral pH and below a critical CaCl2 concentration, NaCas does not aggregate by itself nor co-

aggregates with WPI in the mixtures. The presence of a few Ca2+ ions per protein drove a transition of the

morphology of WPI aggregates from relative small strands to larger spherical microgels causing the

turbidity to increase with increasing CaCl2, see figure 1. Addition of CaCl2 above a critical amount induced

gelation of heated WPI solutions.

Addition of NaCas to the WPI solutions shifted the transition to higher CaCl2 concentrations so that at a

fixed CaCl2 concentration the turbidity of solution decreased with increasing NaCas concentration, see

figure 2. This effect can be understood by the strong affinity of caseinate to bind Ca2+ so that less Ca2+ is

available for WPI. Addition of NaCas also reduced the critical CaCl2 concentration needed to induce gelation

of WPI at 3.4wt%, which can be explained by the competition for Ca2+. Remarkably, however, addition of

more than 6wt% NaCas induced gelation of WPI even in the absence of CaCl2. As a consequence of these

two antagonistic effects, in a limited range of CaCl2 concentrations WPI solutions formed gels at low and

high concentrations of added NaCas, but remained liquid when at NaCas intermediate concentrations.

Figure 1. Heated solutions of WPI at 4wt% and different CaCl2 concentrations indicated in the figure.

Figure 2. Heated solutions of WPI at 3.4 wt% and 2.54 mM CaCl2 with different NaCas concentrations

indicated in the figure.

0 0.5 1 2 3mM

0 0.1 0.3 0.6 0.8 1 3%

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40

MC-4

Mixed biopolymer gels prepared from cellulose microfibrils and whey protein isolate - the role

of cellulose in structuring of foods

Jinfeng PENG1 , Paul VENEMA1 , Krassimir VELIKOV2,3 , Erik VAN DER LINDEN1,2 1 Physics and Physical Chemistry of Foods, Department of Agrotechnology and Food Sciences, Wageningen

University, Wageningen, the Netherlands 2 Unilever R&D Vlaardingen, Vlaardingen, The Netherlands 3 Soft Condensed Matter, Debye Institute for NanoMaterials Science, Utrecht University, Utrecht, The

Netherlands

Bacterial cellulose (BC) has gained increasing interest in the past years due to its high purity compared with

plant cellulose and its remarkable properties such as high aspect ratio, high crystallinity and mechanical

strength. Considerable attention has been received in a variety of research fields, from medical to material

science. In food technology, they are of interest because of their multifunctional properties and potential

use as e.g. thickening, gelling, stabilizing agent, texture modifier and fat substitute. Nevertheless, the

behaviour of bacterial cellulose in complex food systems has not yet been fully exploited and well

understood. Protein and polysaccharide are the two main components in foods, which together contributes

to the structure, texture and stability of the foods. Interactions between protein and polysaccharide can be

varied under different conditions. In this study, we investigated the mixed gel prepared from

microfibrillated bacterial cellulose(MFC) produced from nata de coco and whey protein isolate (WPI) at

neutral pH upon heating. In particular, we investigated their rheology, microstructure and mechanical

properties. Results showed that the mixture of MFC and WPI forms a bicontinuous gel. The gelation of

whey protein isolate is not influenced by the presence of BC, and the addition of BC leads to an increase of

the storage modulus and enhancement of the stiffness and brittleness of the gel. Understanding the

interactions between WPI and BC under different conditions will aid the design of novel structures in foods.

Acknowledgement: This research is financially supported by NanoNextNL (consortium of Dutch

government and 130 other partners).

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41

MC-5

Quantitative confocal microscopy and probe diffusion in bicontinuous phase separated

structures

N. Loren1,4 , E. SCHUSTER1,4 , M. RUDEMO2,4 , A-M. HERMANSSON1,3,4 1 Structure- and Materialdesign, SIK – The Swedish Institute for Food and Biotechnology, Box 5401, SE-402

29 Göteborg, Sweden 2 Mathematical Sciences, Chalmers Univeristy of Technology, SE-412 96 Göteborg, Sweden 3 Department of Chemical and Biological Engineering, Chalmers University of Technology,SE-412 96

Göteborg, Sweden 4 SuMo Biomaterials, VINN Excellent Center, Chalmers University of Technology, SE-41296 Gothenburg,

Sweden

Diffusion is vital for many food properties such as water management in pasta and pastry products, oil

migration induced fat bloom in chocolate and oral taste release. These examples show that it is important

to have good control over the diffusion properties to obtain desired functionality. Therefore thorough

understanding of structure - mass transport relationships at different length scales in the structure and

good measurement techniques for global and local for diffusion are essential. In this talk, the coupling

between structure and diffusion1 at different length scales in Foods and soft porous heterogeneous

materials will be discussed.

Quantitative microscopy allows for simultaneous determination of the detailed microstructure at

micrometer level and local quantitative information regarding mass transport, electrostatic interactions,

rheological properties etc. A brief overview of different microscopy based techniques to characterize local

diffusion will be given in this presentation. Confocal laser scanning microscopy (CLSM) in combination with

Flourescence recovery after photobleaching (FRAP)1 or raster image correlation spectroscopy (RICS) are

versatile methods to determine quantitative diffusion properties locally directly in the microscope. They

can be used in many types of soft porous homogeneous and heterogeneous foods and biomaterials. A new

powerful RICS technique that gives precise measurements on the local diffusion coefficient will be

presented2. In addition, examples from the use of FRAP and RICS will be presented.

Food properties change as a function of time and surrounding conditions. CLSM-FRAP combined with

different stages to control surrounding conditions is powerful to monitor effects of kinetics on the diffusion

properties. Here, results on microstructure and probe diffusion in phase separated biopolymer mixtures

determined by FRAP and NMR diffusometry will be presented3. The effect of the characteristic wavelength

and the equilibrium concentration on the diffusion in bicontinuous phase separated biopolymer mixtures

will be demonstrated using quantitative microscopy and Lattice-Boltzmann simultations. In addition,

possibilities to quantitatively monitor diffusion in alginate gels4 and very recent results that reveal the

effects of charg -

lactoglobulin gels will be presented5.

[1] Lorén et al. (2015) Quarterly Reviews of Biophysics 48, 3 (2015), pp. 323–387.

[2] Longfils et al. (2015) Manuscript submitted to J. Microscopy.

[3] Wassén et al. (2014) Soft Matter DOI: 10.1039/c4sm01513d

[4] Schuster et al. (2014) Soft Matter, DOI: 10.1039/c3sm52285g.

[5] Schuster et al. (2014) Biophysical J., 106, 253 – 262.

Food Colloids 2016

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42

MC-6

Fate of solid lipid nanoparticles (SLN) in o/w emulsions

Kathleen OEHLKE1, Johanna MILSMANN1, Ralf GREINER1, Anja STEFFEN-HEINS2

1 Institute of Food Technology and Bioprocess Engineering, Max Rubner-Institut, Karlsruhe, Germany

2 Institute of Human Nutrition and Food Science, Kiel University, Kiel, Germany

Solid lipid nanoparticles (SLN) have been investigated as carrier systems in pharmaceutical, cosmetic or

food related applications. The potential use of SLN includes the encapsulation of bioactive compounds,

antimicrobials or antioxidants. If SLN are added to food matrices they are likely to interact with other food

components. This presentation will point out several interactions of SLN with o/w emulsions and how they

might affect possible applications or detection methods. Edible SLN were added to o/w emulsions stabilized

by different emulsifiers (SDS, CTAB, Tween 20). The experimental approach to study the interactions

included dynamic and static light scattering, DSC measurements, EPR spectroscopy and lipid oxidation tests.

Interactions between SLN and oil droplets on different length scales were detected. Emulsifiers were

exchanged between SLN and oil droplets leading to altered zeta potentials of SLN and oil droplets. Also,

part of the solid lipid content migrated into the liquid oil phase of the emulsion. Furthermore, the physical

stability of the o/w emulsions could be enhanced by SLN, which was likely a result of the altered interfacial

composition and / or the increased viscosity. SLN used as carriers for antioxidants increased also the

oxidative stability of the oil. This observation might be explained by the migration of encapsulated

compounds from SLN to the oil droplets.

These results imply that detection methods should take into account the release and migration of e.g.

fluorescent labels so that misinterpretations are avoided. The release and migration of encapsulated

compounds is also a drawback of SLN as carrier systems. On the other hand, the gradual release of

substances from SLN and their migration to other components of the food matrix may be interesting for

possible applications.

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43

MC-7

Process stability of whey protein-pectin complexes as new structuring elements in fat-reduced

food systems

Kristin PROTTE1, Alina SONNE1, Jochen WEISS2, Jörg HINRICHS1 1 Department of Soft Matter Science and Dairy Technology (University of Hohenheim, Stuttgart, Germany 2 Department of Food Physics and Meat Science (University of Hohenheim, Stuttgart, Germany)

Pectins and whey proteins are often used as stabilizers in diverse dairy products. Mixing these two

biopolymers in an aqueous solution results in the formation of electrostatically attracting complexes. It is

postulated that these complexes can be used as structuring agents in fat-reduced food systems. However,

since electrostatically-stabilized complexes are highly sensitive to dissociation due to changes in their local

environment, e.g. heating, shearing and ionic strength, a major challenge is to generate whey protein-

pectin complexes that maintain their expected functionalities upon variations in substrate composition and

during processing. The aim of this study was to identify processing conditions to generate process stable

whey protein-pectin particles with improved functional properties in comparison to the biopolymers alone.

For this purpose, we studied the response of those associated complexes to changes in calcium

concentration, shear rates and nature of pectin on different plant scales. Biopolymer mixtures consisting of

native whey protein and pectin with varying distribution of esterification have been generated at a ratio of

5:1. Different concentrations of calcium chloride were added to simulate use of whey. The biopolymer

mixtures were shear-heat-treated for 250 s at 90 °C. Shear rates have been varied at 0-500 s-1 to investigate

process stability under different processing conditions. Generated structures were characterized by means

of particle size, microscopic analysis, and fluorescence spectroscopy. Results revealed that the structural

and mechanical characteristics of whey protein-pectin particles are strongly affected by pectin type and

biopolymer concentration level. In particular, heat treatment is a promising way to generate shear stable

whey protein-pectin complexes which are tolerant towards changes in calcium concentration. Particle size

analysis indicated that pectin-stabilized whey protein aggregates are able to meet size characteristics of

milk fat globules (1 – 10 µm) and thus might have potential to replace parts of fat in fermented dairy

products. This study outlines that functional properties of whey protein - pectin complexes can be designed

towards the desired application in food systems by choice of process parameters.

References:

Krzeminski, A., Prell, K., Weiss, J. and Hinrichs, J. (2014). Environmental response of pectin-stabilized whey protein

aggregates. Food Hydrocolloids, 35, 332 –340.

Salminen, H. and Weiss, J. (2013). Effect of pectin type on association and pH stability of whey protein-pectin

complexes. Food Biophysics, 9, 29-38.

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MC-8

Mechanical properties of extra virgin olive oil based oleogels as affected by minor compounds

Veronica GIACINTUCCI1, Carla DI MATTIA1, Giampiero SACCHETTI1, Saeed M. Ghazani2, Alejandro

G. Marangoni2, Paola PITTIA1 1 University of Teramo, Teramo, Italy 2 University of Guelph, Guelph, Canada

In order to introduce healthier fats in commercial food products, researchers are focusing on the use of

olive oil as a substitute for animal fat.. One of the problem with substituting fat with a liquid oil is the lack

of crystalline fat in the oil, which many time negatively affects the the textural properties of the food

product. The use of an organogelator to structure edible oils is an important means of providing liquid oils

some structure and functionality in the absence of solid fat, hydrogenated or excessively saturated. In this

respect, ethylcellulose (EC) is a promising option since its ability to act as organogelator has been

investigated thoroughly in the past 4 years. However, no data exists in the literature on its use in extra

virgin olive oil (EVOO). The aim of the work was thus to study the structural and mechanical properties of

EVOO-based oleogels structured with EC. In particular, the attention was focused on the interaction of olive

oil’s minor compounds with EC in the different steps of the refining process (degumming, neutralization

and bleaching). At each step, the oils were characterized by means of free fatty acids and polyphenols

content, primary and secondary oxidation products and polarity. The mechanical properties of the oleogels

were investigated by means of large deformation tests whilst the microstructure was studied with Atomic

Force Microscopy (AFM). Results showed that minor compounds can significantly affect the microstructure

and the mechanical properties of the oleogels, with a major role played by oxidation products and the

polarity of the solvent which could influence the gel’s mechanical strength by promoting H-bonding with

EC. Moreover, AFM micrographs show that a higher oxidation index is related to a slightly higher porosity in

the EC network. Free fatty acid concentration and oxidation products have a synergistic effect on the

mechanical properties of the EVOO-based oleogels.

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45

MC-9

Oil Solubilization in cationic surfactant–anionic polymer complexes: Effect of polymer

concentration, temperature and ionic strength

Hui ZHANG1, Lingli DENG1, Jochen WEISS2 1 Zhejiang University, Hangzhou, China 2 University of Hohenheim, Stuttgart, Germany

The surfactant micelles are capable of solubilizing nonpolar molecules into their hydrophobic interiors and

transporting them across an aqueous phase in which they are normally insoluble [1]. Addition of polymers

may alter the ability of oppositely charged surfactant micelles to solubilize hydrophobic molecules

depending on surfactant–polymer interactions [2], leading to the formation of surfactant–polymer

complexes with improved functionalities [3].

This study was conducted to investigate the solubilization thermodynamics of an octane oil-in-water

emulsion in mixtures of an anionic polymer (carboxymethyl cellulose) and cationic

cetyltrimethylammonium bromide (CTAB) surfactant micelles using isothermal titration calorimetry (ITC)

[4]. Results showed that the CTAB binding capacity of carboxymethyl cellulose increased with increasing

temperature from 301 to 323 K or with increasing NaCl concentrations up to 100 mM, and the

thermodynamic behaviors of octane solubilization in CTAB micelles, either in the absence or presence of

polymer, were found to have a strong dependence on temperature or ionic strength. The addition of

carboxymethyl cellulose caused the solubilization in CTAB micelles to be less endothermic, and increased

the solubilization capacity. The increasing ionic strength caused the solubilization in CTAB micelles to be

less endothermic or even exothermic, but increased the solubilization capacity.

Based on the phase separation model [5], the solubilization was suggested to be mainly driven by enthalpy

gains. It is suggested that increasing concentrations of the anionic polymer gave rise to a larger Gibbs

energy decrease and a larger unfavorable entropy increase for octane solubilization in cationic surfactant

micelles, while increasing ionic strength gave rise to a larger Gibbs energy decrease but a smaller

unfavorable entropy increase for octane solubilization in cationic surfactant micelles.

[1] Schick MJ. Nonionic Surfactants: Physical Chemistry. Marcel Dekker: New York, 1987.

[2] Lee LT. Polymer-surfactant interactions: Neutron scattering and reflectivity. Current Opinion in Colloid and

Interface Science, 1999, 4, 205-213.

[3] Asker D, Weiss J, McClements DJ. Analysis of the interactions of a cationic surfactant (lauric arginate) with an

anionic biopolymer (pectin): Isothermal titration calorimetry, light scattering, and microelectrophoresis. Langmuir,

2009, 25, 116-122.

[4] Zhang H, Zeeb B, Salminen H. Isothermal titration calorimetric analysis on solubilization of an octane oil-in-water

emulsion in surfactant micelles and surfactant–anionic polymer complexes. Journal of Colloid and Interface Science,

2015, 438, 7-13.

[5] Lee J, Moroi Y. Solubilization of n-alkylbenzenes in aggregates of sodium dodecyl sulfate and a cationic polymer of

high charge density (II). Langmuir, 2004, 20, 6116-6119.

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46

MC-10

Potato Protein Based Nanovehicles for Health Promoting Hydrophobic Bioactives in Clear

Beverages

Shlomit DAVID1, Yoav D. LIVNEY1 1 Biotechnology & Food Engineering, and Russell Berrie Nanotechnology Institute, Technion, Israel Institute

of Technology, Haifa 3200000, Israel

Vitamin D is a fat soluble nutraceutical of great importance for multi-system function: calcium and bone

metabolism, insulin reactivity, cell differentiation, the immune system and more. However its deficiency is

a pandemic problem, which calls for fortification of staple foods and popular beverages with this vital

micronutrient. Fortifying beverages with vitamin D poses tough challenges especially due to its low

aqueous solubility. We studied the possibility of using potato proteins as protective nanovehicle for

delivery of vitamin D in clear beverage solutions. Potato proteins are produced from a widely available and

inexpensive raw material. They are considered GRAS and non-allergenic. Moreover, Potato proteins are

natural and applicable in vegetarian, vegan and KOSHER PARVE products. Vitamin D3 (VD) – potato protein

nanoparticles were formed in phosphate buffer at pH 2.5 and the solutions obtained were transparent. The

VD – potato protein co-assemblies were much smaller than the VD aggregates without potato protein. The

nanocomplexation provided significant protection and reduced VD losses during pasteurization, and during

simulated shelf life tests under several different sets of storage conditions. Hence potato protein shows

promise as a good protective carrier for VD, and possibly other hydrophobic bioactives, for enrichment of

clear beverages and other food & drink products, to promote human health.

Food Colloids 2016

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47

MC-11

Multilayered interfaces to delay in vitro lipolysis in O/W emulsions

Meinou N. CORSTENS1a, Claire C. BERTON-CARABIN1a, Annemarie KESTER1a, Remco FOKKINK1b,

Johanna M. VAN DEN BROEK1b, Renko DE VRIES1b, Freddy J. TROOST2, Ad A.M. MASCLEE2, Karin

SCHROËN1a 1 Wageningen University, Department of Agrotechnology & Food Sciences, a Food Process Engineering and

b Physical Chemistry and Colloid Science group, Wageningen, the Netherlands 2 Maastricht University Medical Centre, Department of Internal Medicine, division of Gastroenterology-

Hepatology, Maastricht, the Netherlands

Lipid fractions that escape digestion and absorption in the upper gastrointestinal tract are believed to induce feelings of satiety, and to inhibit food intake through the ileal brake mechanism (Maljaars, Peters, Mela, & Masclee, 2008). This could be used to modulate the energy balance and, hence, body weight regulation. However, the gastrointestinal tract is designed to efficiently digest a broad range of foods, and dietary lipids need to be protected to reach the ileum. During digestion, lipolysis takes place at the surface of lipid droplets, where lipase comes into contact with lipid substrate. Hence, encapsulates need to have an oil-water interfacial structure that protects against the action of lipase (Corstens et al., accepted manuscript). In this context, our aim is to develop interfacial structures able to encapsulate dietary lipids and control lipolysis. The present work focused on multilayered emulsions (d32 ~ 5-30 μm), which were produced by sequentially adsorbing oppositely charged biopolymers at pH 3.0 (whey proteins; and pectin or chitosan) as schematically shown in Figure 1. Emulsions with a chitosan layer were not physically stable in simulated intestinal fluid, in contrast to pectin-based emulsions. Adsorbing a second and third interfacial layer considerably delayed lipolysis in these emulsions, while further increase of the number of layers led to similar results. The lipolysis susceptibility of multilayered emulsions could be related to the structural stability of the interfacial layers, which was investigated through confocal fluorescence microscopy (CLSM) and reflectometry. The CSLM results provided details of the multilayer structure, and the reflectometry results showed that when exposed to a neutral pH corresponding to the small intestines (pH 7.0), multilayered interfaces with more than three layers lost their outer layers instantaneously when switching to pH 7.0. In addition, we also found that the conditions used for in vitro digestion greatly affected the rate and extent of lipolysis.

This work shows that lipolysis in emulsions can be substantially delayed by controlling the oil-water interfacial design, which needs to be tuned to the conditions in which the food is ingested. Corstens, M. N., Berton-Carabin, C. C., de Vries, R., Troost, F. J., Masclee, A. A. M., & Schroën, K. (accepted manuscript). Food-grade Micro-encapsulation Systems that May Induce Satiety via Delayed Lipolysis: A Review. Critical Reviews in Food Science and Nutrition, http://doi.org/10.1080/10408398.2015.1057634. Maljaars, P. W. J., Peters, H. P. F., Mela, D. J., & Masclee, A. A. M. (2008). Ileal brake: a sensible food target for appetite control. A review. Physiology & Behavior, 95(3), 271–81.

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48

MC-12

Emulsion and microstructure design based on milk protein and guar gum system for controlled

digestion

Wentao LIU1 and Tim J. FOSTER1 1 Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington campus, Nottingham,

LE12 5RD, UK

There has been a recent surge in research focusing on understanding the breakdown properties of foods in

the gastro-intestinal (GI) tract, with a view to better design food systems that can control digestion with

additional beneficial physiological effects (e.g satiety) to help prevent the obesity epidemic.

The objective of our investigation is to design a new food microstructure, or emulsion, to control digestion

(measured in-vitro). To achieve this, skimmed milk powder (SMP), and low and high molecular weight guar

gum (GG), were used to establish phase diagrams at 5oC and pH 6.5 to better understand the phase

behaviours of the milk protein/guar gum systems. Through the incorporation of oil into these systems with

designed microstructures based on the phase diagram, we will further investigate whether a phase

separated system can control fat digestion.

In this study, the phase diagrams of milk protein, and both low and high molecular weight guar gum

mixtures were measured. As expected, the compatibility was found to increase with decrease in molecular

weight of the guar gum [1]. Confocal laser scanning microscopy (CLSM) clearly shows that the

microstructure was driven by the phase volume ratio, and the oil droplets were entrapped within the

protein enriched phase. Furthermore, the lipid digestibility of the designed microstructures was measured

using the pH Stat method. It showed that the protein content, rather than the guar gum had an influence

on fat digestibility.

Moreover, for a selected tie line on the phase diagram of milk protein and guar gum, a system with a

protein continuous phase structure had a greater lipolysis effect, while polysaccharide continuous phase

structure showed a delayed lipolysis effect; these findings suggest further potential applications for new

food product design in regulating satiety effects by triggering the Ileum Brake mechanism [2], [3].

References

[1] Schorsch.C., A.H. Clark, M.G. Jones and I.T. Norton. (1999). Behaviour of milk protein/polysaccharides systems in

high sucrose. Colloids and Surfaces B: Biointerfaces 12: 317-329.

[2] Maljaars PWJ, et al. Ileum brake: a sensible food target food appetite control. A review. Physiol Behav 2008;

95(3):271-81.

[3] Cummings DE, Overduin J. Gastrointestinal regulation of food intake. J Clin Investig 2007; 117 (1) 13-23.

Food Colloids 2016

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MC-13

Regulation of Lipid Digestion via encapsulation in protein gels with differing structures

T. J. WOOSTER1, J-M. JUAN1, S. ACQUISTPACE1, E. KOLODZIEJCZYK1, A. SARKAR1, L. DONATO1 1 Nestle Research Centre, Lausanne, CH-1000, Switzerland

For the past 10-20 years there has been keen interest in understanding how foods in general and lipids in particular are transformed during consumption, digestion, and absorption. This research has yielded great insight into digestive physiology and the description of different strategies to control digestion. We ourselves, like many other excellent groups have been particularly interested in the regulation of fat digestion because of its high caloric density, strong hedonic appeal and relatively mild satiating power. The main mechanisms that these works have used to regulate fat digestion are to control lipases’ ability to bind to the interface of emulsified fat droplets, either by; inhibiting enzyme activity [1, 2], controlling the composition of the interface [3-6], controlling the area of the interface [7, 8] or encapsulation [9]. A number of groups have demonstrated in vitro and/or in vivo that such approaches can have considerable effects on; the rate [7, 8] and/or the extent [1, 10] of fat digestion. Whilst most of these studies have focused on controlling the adsorption of lipase to the interface of fat droplets, there have been relatively few studies that focus on controlling the transport of lipase to interface, using (protein) hydrogels, for example.[11, 12] In this presentation we will describe how entrapment of lipid emulsions within protein gels of various types impacts the kinetics of fat digestion.[13] We aim to develop a mechanistic understanding of how gel architecture (particularly gel digestibility, porosity, and network architecture) impacts the transport of enzymes/digesta through a protein hydrogel and how this relates to the rate of lipolysis. In addition we will highlight how the mesoscale structure of a protein gel can impact not only the kinetics of fat digestion, but also the time of initiation. We hope these new findings help to evolve our detailed understanding of the digestion in simple systems to more complex mixed food structures.

[1] Carriere, F., Renou, C., Ransac, S., Lopez, V., et al., Effect of Orlistat on lipolysis following standard test meals. Gastroenterology 1999, 116, A543-A543. [2] Daher, G. C., Cooper, D. A., Zorich, N. L., King, D., et al., Olestra ingestion and dietary fat absorption in humans. Journal of Nutrition 1997, 127, 1694S-1698S [3] Chu, B. S., Rich, G. T., Ridout, M. J., Faulks, R. M., et al., Modulating Pancreatic Lipase Activity with Galactolipids: Effects of Emulsion Interfacial Composition. Langmuir 2009, 25, 9352-9360 [4] Sandra, S., Decker, E. A., McClements, D. J., Effect of interfacial protein cross-linking on the in vitro digestibility of emulsified corn oil by pancreatic lipase. Journal of Agricultural and Food Chemistry 2008, 56, 7488-7494. [5] Wickham, M., Garrood, M., Leney, J., Wilson, P. D. G., Fillery-Travis, A., Modification of a Phospholipid Stabilized Emulsion Interface by Bile Salt: Effect on Pancreatic Lipase Activity. Journal of Lipid Research 1998, 39, 623-632. [6] Maldonado-Valderrama, J., Wilde, P., Macierzanka, A., Mackie, A., The role of bile salts in digestion. Advances in Colloid & Interface Science 2011, 165, 36-46. [7] Golding, M., Wooster, T. J., Day, L., Xu, M., et al., Impact of gastric structuring on the lipolysis of emulsified lipids. Soft Matter 2011, 7, 3513-3523 [8] Seimon, R. V., Wooster, T., Otto, B., Golding, M., et al., The droplet size of intraduodenal fat emulsions influences antropyloroduodenal motility, hormone release, and appetite in healthy males. American Journal of Clinical Nutrition 2009, 89, 1729-1736. [9] Li, Y., Hu, M., Du, Y.-M., Xiao, H., McClements, D. J., Control of lipase digestibility of emulsified lipids by encapsulation within calcium alginate beads. Food Hydrocolloids 2010, 25, 122-130 [10] Sjostrom, L., Rissanen, A., Andersen, T., Boldrin, M., et al., Randomized placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients. Lancet 1998, 352, 167-173. [11] Guo, Q., Ye, A., Lad, M., Dalgleish, D., Singh, H., Impact of colloidal structure of gastric digesta on in-vitro intestinal digestion of whey protein emulsion gels. Food Hydrocolloids 2016, 54, 255-265 [12] Guo, Q., Ye, A., Lad, M., Ferrua, M., et al., Disintegration kinetics of food gels during gastric digestion and its role on gastric emptying: an in vitro analysis. Food Funct. 2015, 6, 756-764. [13] Sarkar, A., Juan, J.-M., Kolodziejczyk, E., Acquistapace, S., et al., Impact of P rotein Gel Porosity on the Digestion of Lipid Emulsions. J. Agric. Food Chem. 2015, 63, 8829-8837