The Effect Of Yeasts On Free And Bound Aroma Compounds In The Fermentation Process Of Cabernet Gernischt Dry Red

In this study, using Hexi Corridor geographical Cabernet Gernischt as raw materials,the effect of four kinds of yeasts XR、BM45、RA17and Vintage Red on the physic-chemicalindexes in the fermentation process. Amberlite XAD-2resin was used to extract andseparate the free and bound aroma compounds in Cabernet Gernischt dry redwines,combined with GC-MS qualitative separation,using internal standard forquantitative analysis of aroma components in wine.The study found that the content changes of physical and chemical indicators offour yeast species had different effects in fermentation process of Cabernet Gernischtdry red wines. The content of total acids in fermentation process first increased andthen decreased. After the end of different yeast fermentation,the total acid content wasnot much difference. The values of colour intensity were increasing throughout thebrewing process, colour values were closed to1.202inoculated with yeast Vintage RedRA17and XR after fermented ending, compared with grape juice, they increased4.967times. Colour value was significantly lower than other yeasts of the wine of BM45yeast. Colour tone was rapidly decline then slowly increased of four yeasts. During thealcohol fermentation, the concentration of total phenols were increased.Residualsugar、dry extract and alcohol were in line with the requirements of GB in fermentedending of each wine. Tannin content also had a great difference.The content of alcohols, esters, acids had increased in the fermentation process ofsame kinds of yeast. The type and content of free and bound aroma compounds were notthe same in the fermentation.In particular,yeast Vintage Red was more conducive to releaseterpenoid glycoside bound state aroma compounds. Based on odor activity value and reference literature,12kinds of main free aroma components were determined,they wereethyl acetate,3-methyl-1-butanol,1-heptanol, citronellol, amylacetate,3-hydroxybutyrate,ethylcaproate, phenylethanol,1-hexanol,geranial, geraniol and heptanal.7kinds of mainbound aroma components were determined, they were ethyl acetate,3-methyl-1-butanol,1-heptanol, amyl acetate, phenylethanol,1-hexanol and heptanol. The variation ofβ-glucosidase activity were not same, among them average activity of β-glucosidasevaccination Vintage Red was the highest.