anita oberholster

Anita Oberholster

Overview of the Red and White Wine Mouthfeel Wheels

Introduction• Tastes and tactile sensations• Matrix influence on bitterness + astringency• Phenol composition• Sensory properties of phenolics• Development of red wine mouthfeel wheel• Use of RMFW• Development of white wine mouthfeel wheel

Astringency Perception• Astringency described as “roughing”, “drying”

and “puckering”• Tactile sensation• Mechanism of astringency– Phenols bind with saliva proteins and precipitate– Stripping the mouth of lubrication “drying”– Texture effect of astringency could be due to

precipitated complexes or those in solution

• Astringency is dynamic process– Changes during ingestion and expectoration

Oberholster (2008)

Influences on Astringency + Bitterness

• Ethanol %– Decrease astringency perception– Increase bitterness perception

• Sugar content– Decrease bitterness– No influence on astringency, but more difficult to

perceive

Gawel (1998) Austr. J. Grape Wine Res. 4, p. 74-94

Influences on Astringency + Bitterness

• Other wine compounds such as organic acid have astringent sub-qualities themselves – Also contribute by lowering pH, phenol-protein

interactions

• Polysaccharides and proteins– Binds with tannins, reduce astringency

Gawel (1998) Austr. J. Grape Wine Res. 4, p. 74-94McRae and Kennedy (2011) Molecules 16, p. 2348-2364

Variation within Tasters• Effect of variation in salivary flow rate on

time-intensity scaling of bitterness and astringency– Low-flow; perceive max intensity later, more

intense, persistence longer

Oberholster (2008)

Astringency as a taste

• Average time-intensity curves for astringency in wine upon three successive ingestions: left 20s between ingestions; right 40s between ingestions. Sample uptake and swallowing are indicated by a star and arrow, respectively

Guinard et. al., 1986

Phenolics: Main Contributors to Astringency and Bitterness

• Main phenols (flavonoids) in red wine– Anthocyanins responsible for red color– Flavan-3-ols (ex. catechin, epicatechin)• Oligomers and polymers of flavan-3-ols, so called

proanthocyanidins (PA) or condensed tannins Fig 1

Anthocyanin

Figure 1: Proanthocyanidins

Extension units

Terminal unit

Background – phenols in wine• Extraction during wine making– Anthocyanins from skins• Early during fermentation (3-5 days)

– Seed PA (mDP ~ 10), higher % galloylation– Skin PA (mDP ~ 30), also contain

(epi)gallocatechin units• Increase extraction with temp, % EtOH

Sensory Properties of Flavanols

Gawel et al. (1998) Austr. J. Grape Wine Res.(6) 74

• Monomers more bitter than astringent

• Ratio of astringency to bitterness with mDP

Polymeric Phenols and Astringency• Sensory properties of proanthocyanidins

(PA)– Main contributors to bitterness and astringency– Ratio of astringency to bitterness increase with

mDP

• During wine maturation and ageing– Anthocyanins and PA polymerise with each

other by different mechanisms – Influenced by grape composition, presence of

wood (hydrolyzable) tannins

Gawel et al. (1998) Austr. J. Grape Wine Res.(6) 74; Vidal et al. (2003) J. Sci . Food Agric. (83) 564

Wine pigments

Direct condensation

Mateus et al., (2003) J. Agric. Food Chem. 51: 1919-1923; Reynolds (2010) Managing wine quality.

Flavanyl-vinyl-pyranoanthocyanin

Sensory properties of polymerization products

• How does polymerization reactions/products formed during wine aging influence Mouthfeel?

• Characterization of polymeric pigments– Comparing the polymeric pigment profile of 6

month old and 5 year old Syrah wine from the same vineyard• conc. of polymeric pigments, methylmethine and

vinyl-linked pigments• mDP of wine 4 10

– Development of the Mouthfeel wheelOberholster (2008)

Developing the Mouthfeel wheel• Panel of 14 tasters tasted 72 wines over 6

week period to derive a vocabulary– 6 months to 33 year old red wines (mean 4 yrs)– Mostly Australian Shiraz, Cab. Sauv. Pinot noir,

Grenach

• Another 75 red wines tasted to derive Mouthfeel terms not astringent-like– Influence Mouthfeel

• Investigate standards– Taste standards for astringency not practical

Gawel , Oberholster, Francis (2000) Austr. J. Grape Wine Res.(6) 203-207

Standards for Mouthfeel• Taste standards– Commercial tannins and other• Complex profiles• Tiring, influence subsequent perceptions• Carry-over effects

– Touch standards• Cutaneous sensations similar to those experienced in

the mouth

– Terms not represented by physical standards – well defined

Gawel , Oberholster, Francis (2000) Austr. J. Grape Wine Res.(6) 203-207

Mouthfeel wheel

Gawel , Oberholster, Francis (2000) Austr. J. Grape Wine Res.(6) 203-207

Mouthfeel Wheel Astringency

Gawel , Oberholster, Francis (2000) Austr. J. Grape Wine Res.(6) 203-207

Touch Standards Representing Tactile Sensations

Descriptor Touch standard

Talc Johnson baby powder

Satin Satin cloth

Plaster Gypsum powder

Chamois Moistened chamois

Silk High grade silk cloth

Velvet Velvet felt in direction of the nap

Suede Medium suede leather

Furry Short velour cloth

Fine emery paper 1000 grade emery paper

Corduroy Medium cord cloth

Abrasive 600 grade sandpaper

Hessian Carpet backing

Touch Standards Representing Tactile Sensations

SatinSilk

Suede Velvet

Sandpaper1000 grade

Fur (Furry)

Corduroy

Sandpaper600 grade (Abrasive)

Soft Suede(Chamois)

Burlap (Hessian)

Supplementary Definitions for Astringency Terms

Non-astringent Mouthfeel Terms

Gawel , Oberholster, Francis (2000) Austr. J. Grape Wine Res.(6) 203-207

Using the Mouthfeel Wheel (MFW)• Vidal (2003, 2004) fractionated tannins from

grape material – evaluate with MFW– Larger tannin more astringent and drying than

smaller tannin– Seed tannin more astringent (coarse, drying) than

skin tannin of equivalent size– Indicate ‘Coarseness’ and ‘dryness’ of

astringency increase with galloylation– Methylmethine-bridged flavanols more bitter

than similar tannins

Vidal et al. (2003) J. Sci . Food Agric. (83) 564Vidal et al. (2004) Food Qual. Pref. 15, 209-217.

Using the Mouthfeel Wheel (MFW)• Anthocyanins have no taste or tactile effect

(Singleton and Trousdale, 1992)

• Anthocyanins perceived astringency and “fullness” of model wine (Vidal et al., 2004b)

• Anthocyanins – more pure – no significant contribution to Mouthfeel (Vidal et al., 2004a)

• How do you explain differences between white wine and red wine?

Singleton and Trousdale (1992) AJEV 43, 63-70Vidal et al. (2004a) Food Qual. Pref. 15, 209-217Vidat et al. (2004b) Food Chem. 85, 519-525

Using the Mouthfeel Wheel (MFW)• How do you explain changes in Mouthfeel

observed during aging?– Could polymerization reactions explain changes in

Mouthfeel observed?– Increase mDP proanthocyanidins astringency– Formation of polymeric pigments?

Oberholster et al, (2009) Austr. J. Grape Wine Res. (15) 59-69Singleton and Trousdale (1992) AJEV 43, 63-70Vidal et al. (2004a) Food Qual. Pref. 15, 209-217Vidat et al. (2004b) Food Chem. 85, 519-525

Mouthfeel of different white wine treatments

Oberholster et al, (2009) Austr. J. Grape Wine Res. (15) 59-69

White free run juice

White free run juice + anth

Red wineWhite free run juice + white skins and seeds + anth

White free run juice + white skins + seeds

White free run juice + red skins and seeds

W WA WS WSA WRS RS

Mouthfeel Wheel

Oberholster et al, (2009) Austr. J. Grape Wine Res. (15) 59-69

Medium grain (Bentonite)

Coarse grain (Celite S45 filter aid)

Fine grain (Talcum powder)

Mouthfeel of different white wine treatments

Oberholster, et al.,(2009) Austr. J. Grape Wine Res. (15) 59-69

• W: white free run juice • WA: white free run juice + anth• WS: white free run juice + white skins and

seeds

• WSA: white free run juice + white skins and seeds + anth

• WRS: white free run juice + red skins and seeds• RS: red wine

Conclusion – RW-MFW• Using the MFW – small differences in phenol

content could be related to Mouthfeel differences– Anth increases astringency related terms, mainly

fine grain sub-attributes

• But MFW is difficult to use – needs extensive training

• Doubt wine consumers will be able to use this wheel to communicate in meaningful way

White Wine Mouthfeel Wheel• White wine elicit wide range of taste and

mouthfeel sensations• Pickering et al. (2008) evaluated 136 wines– Table, sparkling, dessert and fortified white wines– Using hierarchical wheel structure– Developed definitions and reference standards

• Tool to aid training and communication between wine professionals– Help define influence of viticultural and

enological variable on white wine quality

White Wine Mouthfeel Wheel

White Wine Mouthfeel Wheel• Some major difference between the white

and red mouthfeel wheel– Contains taste parameters– Avoided terms related to flavor even though

observed retro-nasally– Inclusion of “time dimension” in the wheel– Descriptors are ordered clockwise starting at 12’

noon in approx order of perception and intensity perceived• RMFW has no intensity levels build in

Pickering and DeMiglio (2008) J. Wine Res. 19 (1) p. 51-67

White Wine Mouthfeel Wheel• EtOH %– Elicit tactile sensations • Heat/irritation• Astringent-like drying• EtOH enhance lubricity of oral cavity – reducing the

perception of roughness

• Glycerol– Could contribute to perceived viscosity, reducing

roughness, decreasing astringency

• Polysaccharides can also potentially contribute in similar way as glycerolGawel et al. (2007) Austr. J. Grape Wine Res. 13, p. 38-45

Pickering and DeMiglio (2008) J. Wine Res. 19 (1) p. 51-67

White Wine Mouthfeel Wheel• Discrete sensations

⁻ Used RMFW as reference so some similar terms⁻ Diffr groupings of sensations

White Wine Mouthfeel Wheel• Discrete sensations

⁻ Surface smoothness terms have levels associated

⁻ Satin, silk and chamois are different levels of smoothness⁻ Particulate terms are grouped under surface smoothness

White Wine Mouthfeel Wheel

White Wine Mouthfeel Wheel• Integrated sensations

⁻ These product are associated with sparkling wines⁻ Seems body and weight related

White Wine Mouthfeel Wheel• Integrated sensations

⁻ These product are associated with sparkling wines⁻ Seems body and weight related

Integrated sensations

White Wine Mouthfeel Wheel• Usefulness of WMFW is still unknown• Due to different WMFW and RMFW concepts– Using both wheels will be confusing– Too many complex or integrated terms which is

not well defined– Both wheels can be adapted for personal use– Simplified and clarified further

Thank you• Funding (GWRDC)• Mouthfeel panel

Elizabeth WatersGraham JonesPatrick IlandLeigh FrancisRichard Gawel

Karen BlockLinda BissonLucy JosephKay Bogart

Touch Standards Representing Tactile Sensations

Satin Silk Suede VelvetSandpaper1000 grade

Fur (Furry)

Soft Suede(Chamois)

Sandpaper600 grade (Abrasive)

Burlap (Hessian)Corduroy

Mouthfeel Standards and Definitions

Satin SilkSuede Velvet

Sandpaper1000 grade

Fur (Furry)

Soft Suede(Chamois)

Sandpaper(Abrasive)Burlap (Hessian)

Corduroy