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

  • P.P. Minnaar ARC Infruitec-Nietvoorbija, Private Bag X5026, Stellenbosch 7600, South Africa
  • M. Booyse ARC Biometry Unit, Private Bag X5026, Stellenbosch, Stellenbosch 7600, South Africa

Abstract

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

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Published
2011-12-07
Section
Articles