Taste and textural characters of mixtures of caftaric acid and Grape Reaction Product in model wine

Background and Aims: Caftaric acid and Grape Reaction Product (GRP) are abundant phenolic substances in white wine. Reports of their sensory effects are confined to individual threshold assessments and anecdotal evaluation of their contribution to mouthfeel. This study profiles the taste and texture of mixtures of caftaric acid and GRP when presented at concentrations typical of white wine. Methods and Results: Mixtures of caftaric acid and GRP, isolated from white wine by countercurrent chromatography, were added to a model wine using a 3 x 3 full factorial design, and their taste and texture were profiled by trained assessors. Grape Reaction Product suppressed astringency and added to oily mouthfeel, while caftaric acid suppressed the burning sensation from GRP. Neither GRP nor caftaric acid elicited significant bitterness. Conclusions: Caftaric acid and GRP suppressed textural characters elicited by each other, and also by acidity, without contributing significantly to bitterness. Significance of Study: The ability of caftaric acid and GRP to reduce burning and drying sensations without adding to bitterness suggests that they can potentially contribute positively to white wine texture. Oxidative juice handling may contribute to oily mouthfeel that typifies some wine styles.