Differentiation of young red wines based on chemometrics of minor polyphenolic constituents.

For reasons of examining any possible discrimination of young red wines based on selected, minor polyphenols, a survey was carried out including 35 samples originating from three Hellenic native and three international Vitis vinifera cultivars from various regions of Greece. All samples were experimental wines vinified and stored under identical conditions, in an effort to minimize the effect of different winemaking technologies as well as aging. The polyphenols analyzed belonged to two categories: benzoic acid derivatives, including gallic acid, protocatechuic acid, vanillic acid, and syringic acid, and stilbenes, including astringin, piceid, and resveratrol (all trans isomers). Data handling employing discriminant analysis (DA) yielded very satisfactory categorization of samples in terms of both cultivar and geographical region of origin. This outcome was discussed with regard to the value of certain minor polyphenols that could serve as characteristic indices for discrimination of varietal red wines, after appropriate implementation of chemometrics.

Storage of olives (Olea europaea L.) under CO2 atmosphere: liquid chromatography-mass spectrometry characterization of indices related to changes in polyphenolic metabolism.

Olives (Olea europaea cv. Chondrolia) were stored under a CO2 atmosphere immediately after harvesting for a period of 12 days. Samples obtained at 24-h intervals were analyzed by HPLC to identify components that may reflect changes in the biochemical behavior of the tissue. Four substances were shown to undergo significant fluctuations during storage, while their evolution was found to be different in olives stored under CO2 from those stored under regular atmospheric conditions (control). On the basis of data provided by liquid chromatography-electrospray ionization mass spectrometry, these substances were tentatively identified as hydroxytyrosol glucoside, demethylated ligstroside aglycone, ibotalactone A methyl ester, and verbascoside. The data are discussed in relation to the effect of postharvest treatments of olives for purposes of manipulating their polyphenolic content and plausible development of novel debittering processes.

Differentiation of young red wines based on cultivar and geographical origin with application of chemometrics of principal polyphenolic constituents.

Nineteen major polyphenolic phytochemicals including hydroxycinnamate derivatives, flavanols, flavonols, and anthocyanins, were determined in 40 experimental red wines employing HPLC-DAD. All wines analysed were young (non-aged), produced, and stored under identical conditions, in an effort to minimize the effect of oak wood and vinification technology. The data obtained from this examination composed the matrix for the implementation of chemometrics, which aimed at differentiating the wine samples on the basis of cultivar and geographical region of origin. Discriminant analysis performed at a 95% significance level revealed a very satisfactory categorization of the samples both in terms of cultivar and region of origin, thus illustrating the validity of major phenolic phytochemicals for studies pertaining to wine quality and authenticity.