Adm

ella

Dani

el O

ines

, US

Packaging constitutes a major market share of the Plastic industry desPite its often short term aPPlication. With groWing concerns on the environment and resources, Whey coated Packaging can be the solution for the future that is made from Waste materials and is recyclable. by ElodiE Bugnicourt, innovació i recerca industrial i sostenible (iris)

FEATURES SEPTEMBER 2013 ASIA PACIFIC FOOD INDUSTRY

ters such as polyhydroxyalkanoates (PHAs) are naturally accumulated in microbial cultures.

Others biopolymers, such as polylactic acid (PLA), are obtained from bio-derived monomers, (eg: from corn starch) which are then pol-ymerised through standard routes. This is also the case for the new commercially available bio-based polyethylene therephtalate (PET) or polyethylene (PE), which now covers the biggest segment in terms of pro-duction volume among biopolymers.

HugE MarkEt SHarEWhile generally used for short term application, packaging is the biggest market for the plastic industry with an increasing share of over 40 per-cent of all plastic produced (even accounting for over 70 percent for bioplastics).

In consideration of the legis-lation and market requirements, factors such as weight reduction, re-cyclability, waste reduction, used of sustainable/renewable raw materials have driven new developments in the sector.

64

While maintaining good food preservation just like their synthetic counterparts, biodegradable plastics stands out as a solution for con-serving depleting fossil resources, reducing carbon dioxide emissions and environmental pollution at the end of their packaging lives.

Research enabling the develop-ment of tailored made solutions for this sector is important because most biopolymers do not meet the requirements of packaging for sen-sitive food due to their insufficient barrier properties, which are un-able to guarantee product quality throughout its shelf life.

Such requirements in terms of barriers against light, moisture, wa-ter vapour and gases are specific to the type of food packed. To fulfil the optimal combination of properties, multilayer laminates are generally used. However, due to the challenge of separating the different materials during recycling operations, mul-tilayer flexible packaging is often unrecyclable.

The New whey Of Packaging

As opposed to standard plastics de-rived from petroleum, bio-sourced polymers, hereafter referred to as biopolymers are from renewable bio-mass sources. The use of this class of materials is in fact nothing new.

For example, back in the 40s, Ford introduced an all-plastic motor car body made of cellulose fibre and resin extended with a by-product of the soybean oil extraction process. However, the subsequent interest in this class of materials faded out with the development of more durable and resistant petro-chemical plastics.

Now, having reaching a new breakeven point, research has re-cently been intensified in that field, revealing a large range of possible resources and extending the spec-tra of applications biopolymers can fulfil. This can be attributed to the improvement of their performance, making them more competitive with their synthetic counterparts.

The feedstocks for naturally oc-curring biopolymers range from proteins (from animal and vegetal sources) to lipids and polysaccha-rides (eg: starch and cellulose based biopolymers). Some biogenic polyes-

4pp The New Whey Of Packaging.indd 64 8/26/13 12:01 PM

Adm

ella

Dani

el O

ines

, US

Packaging constitutes a major market share of the Plastic industry desPite its often short term aPPlication. With groWing concerns on the environment and resources, Whey coated Packaging can be the solution for the future that is made from Waste materials and is recyclable. by ElodiE Bugnicourt, innovació i recerca industrial i sostenible (iris)

FEATURES SEPTEMBER 2013 ASIA PACIFIC FOOD INDUSTRY

ters such as polyhydroxyalkanoates (PHAs) are naturally accumulated in microbial cultures.

Others biopolymers, such as polylactic acid (PLA), are obtained from bio-derived monomers, (eg: from corn starch) which are then pol-ymerised through standard routes. This is also the case for the new commercially available bio-based polyethylene therephtalate (PET) or polyethylene (PE), which now covers the biggest segment in terms of pro-duction volume among biopolymers.

HugE MarkEt SHarEWhile generally used for short term application, packaging is the biggest market for the plastic industry with an increasing share of over 40 per-cent of all plastic produced (even accounting for over 70 percent for bioplastics).

In consideration of the legis-lation and market requirements, factors such as weight reduction, re-cyclability, waste reduction, used of sustainable/renewable raw materials have driven new developments in the sector.

64

While maintaining good food preservation just like their synthetic counterparts, biodegradable plastics stands out as a solution for con-serving depleting fossil resources, reducing carbon dioxide emissions and environmental pollution at the end of their packaging lives.

Research enabling the develop-ment of tailored made solutions for this sector is important because most biopolymers do not meet the requirements of packaging for sen-sitive food due to their insufficient barrier properties, which are un-able to guarantee product quality throughout its shelf life.

Such requirements in terms of barriers against light, moisture, wa-ter vapour and gases are specific to the type of food packed. To fulfil the optimal combination of properties, multilayer laminates are generally used. However, due to the challenge of separating the different materials during recycling operations, mul-tilayer flexible packaging is often unrecyclable.

The New whey Of Packaging

As opposed to standard plastics de-rived from petroleum, bio-sourced polymers, hereafter referred to as biopolymers are from renewable bio-mass sources. The use of this class of materials is in fact nothing new.

For example, back in the 40s, Ford introduced an all-plastic motor car body made of cellulose fibre and resin extended with a by-product of the soybean oil extraction process. However, the subsequent interest in this class of materials faded out with the development of more durable and resistant petro-chemical plastics.

Now, having reaching a new breakeven point, research has re-cently been intensified in that field, revealing a large range of possible resources and extending the spec-tra of applications biopolymers can fulfil. This can be attributed to the improvement of their performance, making them more competitive with their synthetic counterparts.

The feedstocks for naturally oc-curring biopolymers range from proteins (from animal and vegetal sources) to lipids and polysaccha-rides (eg: starch and cellulose based biopolymers). Some biogenic polyes-

4pp The New Whey Of Packaging.indd 64 8/26/13 12:01 PM

FEATURES

Whey is a by-product of cheese manufacturing

terised or assessed after lamination with PE as a sealing layer.

BarriEr ProPErtiESThe oxygen transmission rates (OTRs) were measured for the lami-nates. The coating showed a good oxygen barrier (eg: a whey coating

of approximately 12 μm in a PE/PET sandwich allowed an improvement by a factor of 30 of the entire OTR).

The calculated average Q100 values (OTR normalised to 100 μm)

65

WHEy ProtEin SolutionIn this context, the development of a biopolymer-coating within the framework of the EC funded Whey-layer project (FP7 no218340) for plastic films based on whey protein has the potential to replace current synthetic oxygen barrier layers used in food packaging, such as ethylene vinyl alcohol copolymers (EVOH) and is expected to be far reaching in the market.

Whey is a by-product of cheese manufacturing and therefore, as opposed to certain controversial biopolymers, it does not create di-rect food competition. For example in Europe, about 20 million tonnes of whey produced annually is not currently valorised. In addition, the generated waste can be highly pol-luting if not properly handled due to the high organic content of whey.

A recent study, which demon-strated the scale-up ability of the production of the whey-based coat-ing as a preliminary requirement for its commercialisation, built on past academic literature which had not been routed to the industry yet, showing that edible coatings made of whey proteins offered good aroma, fat, humidity and oxygen barriers.

The new bio-coating solution was formulated using whey protein isolates (WPI of high purity above 90 percent) and plasticisers to pre-vent brittleness. The most promising formulations among those evalu-ated at pilot scale were selected for scaling up.

The coating solutions were ap-plied at semi-industrial rates using a tailor made application and dry-ing prototype, which optimises speed and energy consumption to minimise the environmental impact of this manufacturing stage. This process also allowed for the cor-rect structuring of the protein-based coating on the film and governed the barrier properties. Resulting coated films were either directly charac-

ASIA PACIFIC FOOD INDUSTRY SEPTEMBER 2013

Call Brady at (65) 6477 7261 or email us at ContactUS_SA@bradycorp.com for more information. www.bradyid.com.sg

Industries with the likes of food and beverages, pharmaceutical, manufacturing wants to enhance channel efficiency, data sharing, prevention of theft and counterfeits. Brady offers a comprehensive track and trace solutions, comprising of signs and label printers, quality labeling materials, bar codes designing software and imaging based bar code scanners to fulfill your tracking needs.

MANAGEYOUR PRODUCTSWITH EASEBRADY’S TRACK & TRACE SOLUTIONS

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l

4pp The New Whey Of Packaging.indd 65 8/26/13 12:01 PM

EU regulation 10/2011 in terms of glo-bal migration.

In terms of end of life, whey pro-teins can be hydrolysed by different enzymes in specific conditions to make multilayer films recyclable as a result of the separation of the layers made up of conventional plastics.

rEcyclaBilityThe recycling process consists of the shredding of the films, the washing and the separation of plastic flakes thanks to the difference in density between the layers assembled by the whey coating, such as PE and PET, before each can be recycled inde-pendently.

The washing stage of the recy-cling process can be easily adapted by the substitution of chemical deter-gent used with a selected enzymatic detergent. The developed whey-coat-ing could be removed within two hours and is therefore compatible with plastic recycling operations.

The possibility of reusing the recovered films was tested by per-forming mechanical tests showing not too significant changes in prop-erties for the separated PE and PET films.

Finally, preliminary life cycle analysis (LCA) showed that the use of whey-based coating can reduce carbon dioxide emissions and con-sumption of resources in packaging production. Data regarding the differ-ence in the production stage of the whey-coating indicates a 15 percent reduction of environmental impact compared to synthetic counterparts such as EVOH or PA at similar weight.

These figures were obtained on prototype production and could be improved at higher production speed. Nevertheless, in a multilayer film, the layer acting as a barrier is relatively thin (thickness depending on the food to be packed and nature of the barrier layer), leading to a ‘di-lution’ of this advantage.

In the previously reported food storage validation, the PA-based

Whey coated films achieved much superior barrier properties compared to other bioplastics.

of the coating were 0.4 (STP) cubic metres/sq m d bar at zero percent rh. Previously reported values were taken into account for the further representation of the OTR vs. water vapour transfer rate (WVTR).

Whey coated films achieved much superior barrier properties compared to other bioplastics. Re-sults also indicate that the OTR values of whey-based coating ap-proached those of EVOH with high ethylene content and are better than polyamide (PA), which was further used for food storage validation.

These results together with the different previously reported ther-mo-mechanical, optical, adhesion properties of coated PET films, con-sequently determine the suitability of the whey protein-based coatings for packaging application and show the potential to substitute other syn-thetic barrier layers used for food packaging.

In terms of validation of the ob-tained material for food packaging, laminates derived from whey protein-coated films were tested for storing

butter cheese in comparison with fully synthetic reference multilayer films (a PE/PA based laminate of 60 μm).

The overall shelf life was compa-rable in both cases and exceeded the duration of the tests that was speci-fied by the cheese manufacturer. Further tests also showed that those laminates fulfilled food contact com-pliance regulations according to the

Advances in Materials Science and Engineering 5

Table 2: Results of the optical measurement of the oxygen barrier.

Trial OTR 𝑄𝑄𝑄𝑄 whey coating 𝑄𝑄𝑄𝑄100 whey coating(cm3 (STP) m−2 d−1 bar−1) (cm3 (STP) m−2 d−1 bar−1) (cm3 (STP) m−2 d−1 bar−1)

PET 101 — —PET/whey coating/PE 3.1 3.2 0.4

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

1000

10000

Oxy

gen

tran

smiss

ion

rate

23∘ C

/50%

RH

Q100

(cm3 (

STP)

m−2

d−1 b

ar−1

)

Permeability values of typical plastics,

Water vapour transmission rate 23∘C/85→ 0% RH Q100

bioplastics, and wheylayer

PET (oriented)

(g m−2 d−1)

PA 12

PP (oriented)PE-HD

PA 11

PVC-U (oriented) PA 6

PA 66

PVC-UPS (oriented)

PUR-elastomer

PC

PE-LD

Wax/paperCelluloseacetate

Cellulose-acetobutyrate

EVA-copolymer,VAC 20%

EVOH 44%

EVOH 38%EVOH 32%

EVOH 27%

PVDC

Wheylayer

Figure 2: Barrier properties of whey-based layer versus other plastics commonly used in the packaging industry normalized to 100𝜇𝜇𝜇𝜇m.

tends to wet totally the surface of the coated sample over thattime.

3.2. Barrier Properties. TheOTRmeasurement results for thecoated PET films after lamination with PE can be found inTable 2 as measured at standard temperature and pressure(STP). The OTR and the 𝑄𝑄𝑄𝑄100 of the whey coating werecalculated as previously explained. This coating showed agood oxygen barrier and thus an increased oxygen barrierfor the resulting coated and laminated films whereby awhey coating of approximately 12𝜇𝜇𝜇𝜇m in a PE/PET sandwichallowed an improvement by a factor 30 of the OTR of thewhole.The calculated average𝑄𝑄𝑄𝑄100 values of the coating were0.4 cm3 (STP) m−2 d−1 bar−1 at 0% r.h. (Table 2).

The WVTRs of whey-coated PET films were measuredby a gravimetric method at 23∘C/85% → 0% r.h accordingto DIN 53 122-1. The PET laminate showed a water vapourbarrier of 15.8 gm−2 d−1 which is the value of uncoated PET.Thus, it was not possible to calculate the WVTR of the wheycoating.Therefore, previously reported values [24]were takeninto account for the further representation of the OTR versusWVTR (Figure 2).

The oxygen barrier evolution versus humidity was mea-sured depending on the relative humidity of the measuringgas (Table 3). The variation of the oxygen barrier of PETdepending on relative humidity was considered in the cal-culation. Above 50% r.h. calculating the oxygen permeabilityof the whey coating was not possible due to the fact thatthe permeability of one layer became lower or equal to thepermeability of themultilayer structure.TheOTRof thewheycoating was almost constant within the range of 0–30% r.h.At 50% r.h. the 𝑄𝑄𝑄𝑄100 raised slightly from 3.8 to 7.9 cm3 (STP)m−2 d−1 bar−1. The difference between the results reported inTables 2 and 3 at similar conditions (i.e., at 0% r.h.) shouldbe explained by the difference of techniques used. Since theoptical method is used for fast screening whereas the resultsin Table 3 are according to the standardized method, thosewere taken into account in the OTR versus WVTR graph(Figure 2).

As shown in Figure 2, whey-coated films achieved muchsuperior barrier properties compared to other bioplastics (ingreen). Results also indicate that the OTR values of whey-based coating approach those of EVOH with high ethylenecontent and are better than PA which is further used for

FEATURES

WHEy-BaSEd coating can rEducE carBon dioxidE EMiSSionS and conSuMPtion of rESourcES in Packaging Production.

SEPTEMBER 2013 ASIA PACIFIC FOOD INDUSTRY

66

Stev

en D

epol

o, M

iam

i, US

4pp The New Whey Of Packaging.indd 66 8/26/13 12:01 PM

EU regulation 10/2011 in terms of glo-bal migration.

In terms of end of life, whey pro-teins can be hydrolysed by different enzymes in specific conditions to make multilayer films recyclable as a result of the separation of the layers made up of conventional plastics.

rEcyclaBilityThe recycling process consists of the shredding of the films, the washing and the separation of plastic flakes thanks to the difference in density between the layers assembled by the whey coating, such as PE and PET, before each can be recycled inde-pendently.

The washing stage of the recy-cling process can be easily adapted by the substitution of chemical deter-gent used with a selected enzymatic detergent. The developed whey-coat-ing could be removed within two hours and is therefore compatible with plastic recycling operations.

The possibility of reusing the recovered films was tested by per-forming mechanical tests showing not too significant changes in prop-erties for the separated PE and PET films.

Finally, preliminary life cycle analysis (LCA) showed that the use of whey-based coating can reduce carbon dioxide emissions and con-sumption of resources in packaging production. Data regarding the differ-ence in the production stage of the whey-coating indicates a 15 percent reduction of environmental impact compared to synthetic counterparts such as EVOH or PA at similar weight.

These figures were obtained on prototype production and could be improved at higher production speed. Nevertheless, in a multilayer film, the layer acting as a barrier is relatively thin (thickness depending on the food to be packed and nature of the barrier layer), leading to a ‘di-lution’ of this advantage.

In the previously reported food storage validation, the PA-based

Whey coated films achieved much superior barrier properties compared to other bioplastics.

of the coating were 0.4 (STP) cubic metres/sq m d bar at zero percent rh. Previously reported values were taken into account for the further representation of the OTR vs. water vapour transfer rate (WVTR).

Whey coated films achieved much superior barrier properties compared to other bioplastics. Re-sults also indicate that the OTR values of whey-based coating ap-proached those of EVOH with high ethylene content and are better than polyamide (PA), which was further used for food storage validation.

These results together with the different previously reported ther-mo-mechanical, optical, adhesion properties of coated PET films, con-sequently determine the suitability of the whey protein-based coatings for packaging application and show the potential to substitute other syn-thetic barrier layers used for food packaging.

In terms of validation of the ob-tained material for food packaging, laminates derived from whey protein-coated films were tested for storing

butter cheese in comparison with fully synthetic reference multilayer films (a PE/PA based laminate of 60 μm).

The overall shelf life was compa-rable in both cases and exceeded the duration of the tests that was speci-fied by the cheese manufacturer. Further tests also showed that those laminates fulfilled food contact com-pliance regulations according to the

Advances in Materials Science and Engineering 5

Table 2: Results of the optical measurement of the oxygen barrier.

Trial OTR 𝑄𝑄𝑄𝑄 whey coating 𝑄𝑄𝑄𝑄100 whey coating(cm3 (STP) m−2 d−1 bar−1) (cm3 (STP) m−2 d−1 bar−1) (cm3 (STP) m−2 d−1 bar−1)

PET 101 — —PET/whey coating/PE 3.1 3.2 0.4

0.01 0.1 1 10 100 10000.01

0.1

1

10

100

1000

10000

Oxy

gen

tran

smiss

ion

rate

23∘ C

/50%

RH

Q100

(cm3 (

STP)

m−2

d−1 b

ar−1

)

Permeability values of typical plastics,

Water vapour transmission rate 23∘C/85→ 0% RH Q100

bioplastics, and wheylayer

PET (oriented)

(g m−2 d−1)

PA 12

PP (oriented)PE-HD

PA 11

PVC-U (oriented) PA 6

PA 66

PVC-UPS (oriented)

PUR-elastomer

PC

PE-LD

Wax/paperCelluloseacetate

Cellulose-acetobutyrate

EVA-copolymer,VAC 20%

EVOH 44%

EVOH 38%EVOH 32%

EVOH 27%

PVDC

Wheylayer

Figure 2: Barrier properties of whey-based layer versus other plastics commonly used in the packaging industry normalized to 100𝜇𝜇𝜇𝜇m.

tends to wet totally the surface of the coated sample over thattime.

3.2. Barrier Properties. TheOTRmeasurement results for thecoated PET films after lamination with PE can be found inTable 2 as measured at standard temperature and pressure(STP). The OTR and the 𝑄𝑄𝑄𝑄100 of the whey coating werecalculated as previously explained. This coating showed agood oxygen barrier and thus an increased oxygen barrierfor the resulting coated and laminated films whereby awhey coating of approximately 12𝜇𝜇𝜇𝜇m in a PE/PET sandwichallowed an improvement by a factor 30 of the OTR of thewhole.The calculated average𝑄𝑄𝑄𝑄100 values of the coating were0.4 cm3 (STP) m−2 d−1 bar−1 at 0% r.h. (Table 2).

The WVTRs of whey-coated PET films were measuredby a gravimetric method at 23∘C/85% → 0% r.h accordingto DIN 53 122-1. The PET laminate showed a water vapourbarrier of 15.8 gm−2 d−1 which is the value of uncoated PET.Thus, it was not possible to calculate the WVTR of the wheycoating.Therefore, previously reported values [24]were takeninto account for the further representation of the OTR versusWVTR (Figure 2).

The oxygen barrier evolution versus humidity was mea-sured depending on the relative humidity of the measuringgas (Table 3). The variation of the oxygen barrier of PETdepending on relative humidity was considered in the cal-culation. Above 50% r.h. calculating the oxygen permeabilityof the whey coating was not possible due to the fact thatthe permeability of one layer became lower or equal to thepermeability of themultilayer structure.TheOTRof thewheycoating was almost constant within the range of 0–30% r.h.At 50% r.h. the 𝑄𝑄𝑄𝑄100 raised slightly from 3.8 to 7.9 cm3 (STP)m−2 d−1 bar−1. The difference between the results reported inTables 2 and 3 at similar conditions (i.e., at 0% r.h.) shouldbe explained by the difference of techniques used. Since theoptical method is used for fast screening whereas the resultsin Table 3 are according to the standardized method, thosewere taken into account in the OTR versus WVTR graph(Figure 2).

As shown in Figure 2, whey-coated films achieved muchsuperior barrier properties compared to other bioplastics (ingreen). Results also indicate that the OTR values of whey-based coating approach those of EVOH with high ethylenecontent and are better than PA which is further used for

FEATURES

WHEy-BaSEd coating can rEducE carBon dioxidE EMiSSionS and conSuMPtion of rESourcES in Packaging Production.

SEPTEMBER 2013 ASIA PACIFIC FOOD INDUSTRY

66

Stev

en D

epol

o, M

iam

i, US

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FEATURES

For more information,ENTER No: 0661

reference films used had a higher thickness than the film based on the whey coating (60 μm compared to 45 μm). The further saving due to weight reduction resulted in a 60-65 percent lower impact during produc-tion and processing of the multilayer fi lms, while still competing in terms of food preservation.

When comparing the two lami-nated materials previously used for food packaging throughout their life cycles, no obvious differences can be identified during the transport, use and manufacturing processes since the impact of co-extrusion and lami-nation are not signifi cantly different.

The reduction of emissions and energy consumption due to the pos-sibility of recycling the polymeric layers of the multilayer film, which are conventionally incinerated, facili-tate a benefi t of 19 percent for human health, 35 percent on ecosystem quality and 14percent on resources when multilayer films based on whey-coating were compared with those based on EVOH.

In the case of the multilayer fi lms of 45 μm based on the whey coating compared with PA-based fi lms of 60 μm, the difference in impact is over 60-80 percent reduction in the impact categories.

It seems that, especially in the field of packaging, the environmen-tal advantages of biopolymers, such as whey protein based coatings, are tremendous over traditional plastics.

EnVironMEntally friEndly oPtionBioplastics can be produced from an increasing range of renewable resources, including an increase uti-lisation of waste materials which are of non-food competing sources as op-posed to bioplastics which diverted full corn fi elds for the production of ethanol leading to starvation and ethical questionings.

Although the research in bioplas-tics is very dynamic, there are still much to be done ahead. The whey

protein based coatings developed in the study exhibited excellent bar-rier properties, outperforming most existing biopolymers and therefore, appear as promising replacements for synthetic barrier used for food packaging applications.

Coated films were validated for storing various food products. The developed whey coating can be re-moved inside the multilayer fi lms to make them recyclable. A LCA has been performed and showed a signifi -cant reduction in the environmental impact of the packaging thanks in particular to the possibility of recy-cling the materials as opposed to incinerating those containing EVOH or PA and also the use of bio-sourced raw materials that are by-product of the industry.

All in all, the whey protein coat-ing safeguards the performance of

packaging and improved the uses resources throughout its life cycle. As a result of this, there are a lot of new opportunities to close the loop between the food and packaging in-dustries with the development of sustainable biopolymers that will help save food and reuse wastes.

67

ASIA PACIFIC FOOD INDUSTRY SEPTEMBER 2013

*Source of the coauthors of this work and article whereby the present results are further described: E Bugnicourt, M Schmid, O Mc Nerney, J Wildner, L Smykala, A Lazzeri, P Cinelli, Processing and Validation of Whey-Protein-Coated Films and Laminates at Semi-Industrial Scale as Novel Recyclable Food Packaging Materials with Excellent Barrier Properties, Advances in Materials Science and Engineering, volume 2013, Article ID 496207, 10 pages, 2013).

Blk 171 Kampong Ampat #03-13/14, KA FoodLink Singapore 368330Tel: (+65) 6286 1360 • Fax: (+65) 6286 5034 e-Mail: enquiry@foodtech.com.sg

LACTO ASIA PTE LTD

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3464

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that fulfi ll your needs.

Call us at +65 6286 1360 or email us at enquiry@foodtech.com.sg on time for your success.

4pp The New Whey Of Packaging.indd 67 8/26/13 12:01 PM