Effects Of Fermentation Temperatures And Impregnation Duration On Cabernet Sauvignon Wines

Polyphenols are an important nutrient for wine,providing color and mouthfeel properties.Grape skin and grape seed are the main sources of wine polyphenols.As the fermentation progresses,the polyphenols that are impregnated in the wine will undergo further complex chemical changes,such as the polymerization of tannins and anthocyanins,and anthocyanidic Hydrolysis and the like.Polyphenols can be transferred from the skin and seeds to the wine only when the grape skin residue is in contact with the grape juice.As the pomace separates,the extraction of polyphenols is terminated.At the same fermentation temperature,the length of the impregnation duration directly determines the content of polyphenols in the wine.When the impregnation duration is the same,different fermentation temperatures will affect the extraction rate of polyphenols and the corresponding chemistry of polyphenols.The change ultimately affects the composition of the polyphenols in the wine.Therefore,the impregnation duration and the alcohol fermentation temperature before the separation of the pomace are the key factors affecting the polyphenol content of the wine.It is of great significance to study the polyphenol extraction rule under different fermentation temperatures and impregnation duration.According to the actual situation of wine production,this study set different fermentation temperatures(20 ° C,24 ° C,28 ° C)and different impregnation duration(80 h,96 h,112 h,136 h,160 h),combined with instrumental testing and sensory evaluation To study the effects of fermentation temperature and impregnation duration on the polyphenol content,antioxidant activity and sensory quality of Cabernet Sauvignon wine,explore the extraction rule of phenolic substances,and provide certain data reference and guidance for wine production.The main results are as follows:(1)Under the same impregnation duration,the test set temperature has little effect on the total phenol of wine.The impregnation duration has a significant effect on the total phenolic content of the wine,and prolonging the impregnation duration can significantly increase the total phenol content.The fermentation temperature affected the total anthocyanin and total tannin of the wine.Under the same impregnation duration,the total anthocyanin in the wine decreased with the increase of fermentation temperature.With the increase of fermentation temperature,the total tannin content increased significantly.However,when the impregnation duration was increased to 136 h,the fermentation temperature did not affect the total tannin content of the Cabernet Sauvignon wine sample,which may be related to the saturation of the tannin content in the long-term impregnated wine.(2)Fermentation temperature affects the sensory quality of wine: 24 ? alcohol fermentation,impregnation 96 h(B2)treatment is conducive to brewing Cabernet Sauvignon wine with high color saturation and purple red or ruby red color,color characteristics tend to new wine;20 ? alcohol fermentation It is conducive to the accumulation of aroma of Cabernet Sauvignon wine;Cabernet Sauvignon wine fermented at 28 ? is superior to 20 ? and 24 ? alcohol fermentation group in appearance,color,gloss and clarity.(3)It is determined that the phenolic antioxidant capacity is not only the total phenolic content,but also the monomeric phenol which is related to it has a certain influence on it.Correlation data showed that there was a significant correlation between total phenol and DPPH and ABTS: total phenol vs DPPH free radical scavenging rate(r = 0.324),total phenol vs ABTS free radical scavenging rate(r = 0.501).It is indicated that there is a positive correlation between the antioxidant capacity of phenols and the total phenolic content.Among the monomeric phenols,gallic acid,caffeic acid,epicatechin,p-coumaric acid,ferulic acid,coumarin,catechin,hesperidin and resveratrol have strong correlation with total phenol.In the DPPH free radical scavenging test,gallic acid,catechin,epicatechin and DPPH free radical scavenging showed a certain correlation.There was a significant correlation between gallic acid,benzoic acid,catechins and p-coumaric acid and ABTS free radical scavenging rate.Combined with DPPH free radical scavenging test and ABTS free radical scavenging test,gallic acid,catechin and p-coumaric acid showed high correlation with free radical scavenging rate.It indicated that the three monomeric phenols of gallic acid,catechin and p-coumaric acid were positively correlated with the antioxidant capacity of wine polyphenols.(4)Through the principal component analysis of the alcohol-like monomer phenol,it was found that: alcohol fermentation at 28 ?,impregnation for 160 h(C5)facilitated the extraction of mulberry pigment in Cabernet Sauvignon;alcohol fermentation at 28 ?,impregnation for 136 h(C4)Conducive to the extraction of resveratrol in Cabernet Sauvignon;alcohol fermentation at 28 ?,impregnation for 112 h(C3)helps to increase epicatechin,gallic acid,catechin in Cabernet Sauvignon wine,ferulic acid,caffeic acid,coumarin,rutin and vanillic acid.(5)Through the principal component analysis of the anthocyanin of the wine sample,it was found that: alcohol fermentation at 20 ?,impregnation for 160 h(A5)can help to increase monosaccharide Mv,monoglycoside Dp,acetylated Pn-acet and The content of acetylated Pt-acet.Alcohol fermentation at 20 ?,impregnation for 112 h(A3),alcohol fermentation at 20 ?,immersion for 136 h(A4),alcohol fermentation at 24 ?,immersion for 136 h(B4)is beneficial to the leaching of caffeoyl Mv-coum in Cabernet Sauvignon wine While alcohol fermentation at 28 ?,impregnation for 112 h(C3)is beneficial to the leaching of monoglycoside Cy and acetylated Dp-coum in Cabernet Sauvignon.