Polyphenols, Anthocyanins, And Aroma Components In Wines From Western Australian

Thirty-six red wines and six white wines from Western Australia were analysed for theiranthocyanins, polyphenols, trans-resveratrol by means of high performance liquidchromatography (HPLC). Aromas from above thirty-six red wines and six white wines wereanalysed using solid phase extraction gas chromatography-mass spectrometry (SPE-GC-MS).The principal aim of this study was to clarify the possibility of correlating the levels of thesecompounds with the variety, origin and vintage of the wine and to use the properties of thesecompounds for wine classification. The discriminant analysis was used to form thediscriminatory function for the prediction of the wine classification. The main results weresummarized as follows:(1) Total phenol, anthocyanins, polyphenols, trans-resveratrol and aroma concentrationsof5varietal wines and4blended wines were examined for the discrimination among grapevarieties. The total phenol levels of red wines from Western Australia were0.99-2.56mg/L,which are almost10folds as white wines (0.14-0.38mg/L). Of the3anthocyanins, thecontent of malvidin-3-glucoside was the highest while cyanidin-3-O-glucoside was thelowest in red grape varieties. Cyanidin-3-O-glucoside was positively correlated withdelphindin-3-O-glucoside. Three anthocyanins were not detected in all white wines. Varietyhad a dramatic effect on the contents of gallic acid, syringic acid, trans-resveratrol, quercetin,myricetin and the ratio of catechin/epicatechin (P＜0.05). Aromas including ethyl hexanoate,ethyl octanoate, isomayl acetate, hexyl acetate and three fatty acids (octanoic acid, decanoicacid and hexanoic acid) can be used to identify red wines and white wines. The levels of ethylvalerate and cis-3-hexen-1-ol had significant difference between Cabernet Sauvignon andShiraz wine (P＜0.05). Pinot Noir wine was differed from Cabernet Sauvignon by isomaylacetate, isoamyl alcohol, hexanol, trans/cis-3-hexenol, benzyl alcohol, phenylethyl, ethylbutyrate and ethyl valerate. Ethyl valerate, isoamyl alcohol, decanoic acid, benzealdehyde,phenylethyl, ethyl laurate, ethyl hexanoate, hexyl acetate, trans/cis-3-hexenol, geraniol can beused to classify Chardonnay from blended white wine.(2) Anthocyanins, polyphenols, trans-resveratrol and aroma concentrations of CabernetSauvignon wines from3geographical origins and Shiraz wines from2geographical originsof Western Australia were assessed for the discrimination among origin wines. Origin hadno obvious effect on the anthocyanins (P＞0.05) but on non-anthocyanin ployphenol, which had significant effect on the levels of trans-resveratrol, myricetin, and epicatechin. The levelsof ethyl valerate, trans/cis-3-hexenol, ethyl octanoate, ethyl decanoate, ethyl laurate, ethylhexadecanoate，geraniol, isoamyl alcohol, octanoic acid and phenylethyl alcohol differedobviously among Cabernet Sauvignon wines from3origins. The concentrations of ethylhexanoate, ethyl octanoate, ethyl decanoate, ethyl laurate, ethyl hexadecanoate，geraniol,hexanoic acid and benzyl alcohol in the Frankland River Shiraz wine were significantlyhigher than that in Margaret River Shiraz wine. Ethyl ester took an important role in theclassification of the wines from different origins. Ethyl decanoate and ethyl hexadecanoatecan be used as an index to classify the Cabernet Sauvignon and Shiraz wine from differentorigins.(3) Total phenol, anthocyanins, polyphenols, trans-resveratrol and aroma concentrationsof7vintage Cabernet Sauvignon wines and4vintage Shiraz wines were examined for thediscrimination among vintage wines. The results showed that the total phenol contents weresignificantly varied in different vintage samples with an irregular pattern (P＜0.05). With theextension of vintage years, the total content of3anthocyanins decreased97.7%in exponentialform, delphindin-3-glucoside decreased from28.26to0mg/L, and malvidin-3-glucoside waslinearly decreased by97.2%. Vintage almost had no effect on the non-anthocyanins phenol,especially during the years of2004-2007. Compared to variety and origin, vintage had lesseffect on the levels of phenols and aroma. There were only8aroma compounds differingamong Cabernet Sauvignon wines from different vintages, and7aroma compounds for Shirazwines. Ethyl succinate, isomayl acetate, trans-3-hexen-1-ol and benzyl alcohol were taken asthe indices to differ the Cabernet Sauvignon and Shiraz wines from different vintages.(4) Discriminant functions were set by the selected phenolic and aroma compounds toclassify wines on the basis of variety, origin and vintage. Discriminatory analysis performedat95%significance level revealed a98.4%categorization of wines in terms of variety,100%categorization of Cabernet Sauvignon and Shiraz wines in terms of origin, and93.8%and86.4%categorization of Cabernet Sauvignon and Shiraz wines in terms of vintage. Our resultsindicated the analytical differentiation of those wines by means of the phenol and aromafunction could support their protection against fraud in the context of variety, origin andvintage.