Differentiation among Young and Market-ready Cabernet Sauvignon, Pinotage and Shiraz Wines: Application of Canonical Discriminant Analysis using Flavonoid and Non-Flavonoid Compositional Data

Various factors affect the polyphenol compound concentrations of red grapes. These include cultivar,vineyard location, viticultural practices, microclimate, soil type and winemaking processes. Polyphenolcompound concentrations of young and market-ready Cabernet Sauvignon, Pinotage and Shiraz wineswere examined for the purpose of discrimination between grape cultivars. Thirty-five individual polyphenolcompounds were quantified using a HPLC-DAD method. Stepwise discriminant analysis (SDA) was usedto select a subset of discriminatory variables. In addition, data was grouped and investigated by canonicaldiscriminant analysis, which showed that polyphenol concentrations can be used to discriminate amonggrape cultivars, young wines and market-ready wines. Flavonol, flavanol and anthocyanin patternswere used as a basis for differentiation of young wines, while flavanols and phenolic acids were used fordifferentiation of market-ready wines. Discriminant analysis performed at 95% significance level revealeda 100% categorisation of market-ready and young wines in terms of cultivar and 77.85% categorisation ofa combination of market-ready and young wines in terms of grape cultivar. This illustrates the validity ofpolyphenols for studies pertaining to grape cultivar discrimination