Chapter 6C
Proteins
Elizabeth Joy Waters and Christopher Bruce Colby
Contents
6C.1 Introduction...................... ........................................ 213
6C.2 TheOriginofWineProteins ................................................ 214
6C.3 CharacterizationofWineProteins............................................ 215
6C.3.1 Size ............................................................. 215
6C.3.2 IsoelectricPoint ................................................... 215
6C.3.3 Stability.......................................................... 215
6C.3.4 LevelsinWhiteWines.............................................. 216
6C.4 Effect of Growing and Harvesting Conditions on Subsequent Wine Protein Levels... 216
6C.4.1 Fungal Infection........... ........................................ 217
6C.4.2 WaterStress ...................................................... 218
6C.4.3 MechanicalHarvesting ............................................. 218
6C.5 HazeFormationinWine.................................................... 219
6C.6 BentoniteFining .......................................................... 220
6C.6.1 TheSensoryImpactofBentoniteFining............................... 222
6C.7 ImprovingBentoniteEfficiency.............................................. 223
6C.7.1 Predictive Assays for Heat Stability............................. ...... 223
6C.7.2 SelectinganAppropriateBentoniteType .............................. 224
6C.7.3 In-LineDosingofBentonite......................................... 224
6C.8 Summary ................................................................ 225
References ............................................................... 226
6C.1 Introduction
Grape and wine proteins have been of interest to winemakers for many years. This
interest is primarily due to the ability of these proteins to aggregate together in
finished white wines and form unattractive hazes and sediments. Proteins are signif-
icant in wine because they are a nuisance!Endogenous wine proteins, of course, also
have other roles in wine and have been examined for their impact on the aroma and
E.J. Waters (B)
The Australian Wine Research Institute, PO Box197, Glen Osmond,
SA 5064, Australia
e-mail: [email protected]
M.V. Moreno-Arribas, M.C. Polo (eds.),Wine Chemistry and Biochemistry,
DOI 10.1007/978-0-387-74118-59,©CSpringer Science+Business Media, LLC 2009
213