The Effect Of Grape Skins And Seeds On The Physical And Chemical Properties And Sensory Quality Of Red Wine

Phenolic compounds were rich in wines and which play a vital role in the sensory qualities of wines.The phenolic compounds in wine,mainly derived from grape skins and grape seeds by maceration,and were related to the quality of the grapes and the winemaking process.The breaking method,maceration time and maceration temperature of grape skins and seeds have a significant influence on the content,composition and source of phenolic compounds,which further affects the color and sensory quality of wine.Therefore,in this study,the grape skins and seeds of different breaking methods were extracted with simulated wine,and the effects of different treatments on wine phenolic substances were analyzed.The effect of different treatments on wine astringency were determined by SDS-PAGE electrophoresis and fluorescence quenching.A process technology for improving the quality of wine by adding grape pomaces was established.The physical and chemical indicators of the wine were determined by the above method.Using the data obtained by principal component analysis,the following conclusions were drawn:1.Different ways of breaking the grape skin and grape seed significantly affect the extraction of phenolic compounds.After shearing,grinding and spiral pressing,the phenols,the mDP(mean degree of polymerization)of proanthocyanidins and the binding strength to salivary proteins of grape skin significantly enhanced,and that of grape skin after the spiral pressing treatment were the most obvious.However,the anthocyanins of grape skin were not changed obviously.After shearing,grinding and spiral pressing,the phenols,flavanols,the mDP(mean degree of polymerization)of proanthocyanidins and the binding strength to salivary proteins of grape seed significantly enhanced,and the phenols,flavanols of grape seed after the light grinding treatment were the most obvious,and that after the shearing treatment were less obvious;the mDP of grape seed after the screw press treatment was largest,and that after the shear treatment was smallest.The change of L*value,a*value and H value of the grape skin extraction after the avulsion treatment was the most obvious.That of the grape seed extraction after the grinding treatment was most obvious.However,after the grinding treatment the b*value of the grape skins and seeds extraction was most obvious.2.During the wine maceration process,the content of phenolic substances,anthocyanins and flavanols increased gradually with the increase of immersion time.Besides,the content of phenolic substances and flavanols were increased significantly after 8 days of maceration while anthocyanins increased significantly after 2 days of maceration;The mainly flavan-3-ol monomer in wine were catechin(C)and epicatechin(EC);The maceration process had no significant effect on the degree of polymerization of proanthocyanidins.However,as the maceration time increased,the ability of wine to bind with protein were increased and then decreased,and the astringency intensity reached the maximum during the five days of maceration.As the maceration time increased,the color of the wine got darker and redder.3.A process technology by adding grape pomaces to improve wine quality was established,and it was determined that the appropriate amount of grape skin residue(10%-20%)significantly increased the phenolic content of the wine and further improved the color and Sensory quality of the wine.In addition,the addition of excessive grape pomaces resulted in a significant decrease in the phenolic content,in the texture structural sense and protein binding capacity of wine.In summary,based on the existing wine brewing process,the paper further determined the influence of breakage of grape skins and seeds and maceration period on the physical and chemical properties and sensory properties of wine,and established a theoretical basis for the industrial application of wine brewing in China.