Primarily grape derived, wine polyphenols are extracted from the skins and seeds. These compounds are diverse, representing multiple classes with a range of molecular sizes and structures. Polyphenols significantly impact color, taste, mouthfeel and the aging potential of wine. It is also well known that production practices can modify the bulk concentration of phenolics in the final wine. Analytical methods that allow for an understanding of the qualitative changes in the phenolic profile can increase the understanding of the relationships between wine production and polyphenol composition. Here, we used a nontargeted analytical approach using UHPLC-qTOF MS to evaluate the distribution of wine polyphenolics in Merlot wine produced using various cap management and maceration practices. Cap management and maceration describe techniques that manipulate the contact between juice and grape solids during wine production; these practices influence the extraction of phenolic compounds with the intent of altering taste and mouthfeel. Phenols were separated chromatographically with hydrophilic interaction chromatography (HILIC) using a glycan stationary phase operating with a binary gradient of acidified acetonitrile and methanol-water. Using this approach, resolution of proanthocyanidin isomers was achieved, allowing for relationships between polymerization and winemaking technique to be observed. Multivariate analysis of the UHPLC-qTOF MS polyphenol measurements discriminated the nine different maceration treatments and longer maceration times produced proportional increases in specific polyphenol compounds. Extraction patterns and sensory implications will be reported for specific compounds and compound classes.

UHPLC-qTOF MS analysis of phenols in wines made with different maceration techniques

253rd National Meeting (2017)

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