The Change Of Organic Acids In The Brewing Process Of Wine And The Reaction Rate

The wine could only be broken or not broken fresh fruit grapes or grape juice after fully or partially alcohol fermentation beverage, Production of wine turned grapes which was a biological product into wine which was another biological product. Caused the transformation of the main medium was called a yeast microbes. So the wine was a biological product, from its grapes mature, the results of the complex b iological transformation which was the transformation of the yeast and bacteria and a series of orderly wine in the bottle. This topic determines malic acid、 citric acid、 pyruvic acid、 lactic acid、succinic acid、 alpha ketone glutaric acid、fermentation yeast dry weight、reducing sugar and yeast alcohol content determination method, fermentation yeast dry weight, reducing sugar and alcohol content needed to determine by colorimetric method, the relative deviation was less than 1%, and experiment found that interference of other ingredients could be ignored for determination methods of grape juice, through concentration gradients measured the absorbance value, dra w the standard curve and regression equation was obtained. experiment used HPLC(High Performance Liquid C hromatography) to determinate the content of organic acid in wine fermentation process includes malic acid, citric acid, pyruvic acid, etc. Via detecting, Determination conditions(Unitary C18(4.6mm×250mm,5μm);Mobile phase: KH2PO4(0.02mol/L,PH:2.4);Detection wavelength: 210 nm; Column temperature: 30℃; The velocity: 0.8 ml/min) were good at the separation of organic acids of grape juice, the correlation coefficient of standard curve of Malic acid、citric acid、pyruvic acid、lactic acid、succinic acid、alpha ketone glutaric acid was more than 0.99, through the regression equation calculated the change of the content in wine fermentation process.The conditions of wine fermentation included temperature was 20℃ and sugar content was19%、temperature was 20℃ and sugar content was 30%、temperature was 30℃ and sugar content was 19%、temperature was 30℃ and sugar contentwas 30%,results of experiment were calculated by Logistic equation and Luedeking-piret equation, experimental data was used to construct yeast cell kinetics equation model, product to generate dynamic equation model, intermediate metabolites dynamics equation model and dynamics equation of the substrate consumption model,We put malic acid, citric acid, lactic acid, pyruvic acid, succinic acid, alpha ketone glutaric acid, reducing sugars, yeast growth, alcohol to nonlinear fitting through origin8.6 software, the data of the correlation coefficients of above 0.90, could be concluded that the calculated value of dynamic equation could better fit with the experimental data,could be concluded that the calculated value of dynamic equation could better fit with the experimental data.Experiment showed that the change and different of each parameter in grape juice by comparing the different fermentation conditions, which was in order to analyze the yeast growth rate with reducing sugar, alcohol degrees, malic acid, citric acid, lactic acid and pyruvic acid and other organic acids, Through analysis, initial energy source of wine fermentation process was mainly rely on EMP to provide energy, and late fermentation was found that it needed other ways to get energy, also appear the change of organic acids.Kinetic equations were nonlinear fitted by origin8.6 were need to differential calculate, and calculate every 24 h metabolic of various parameters, listed the main metabolic network nodes, and built node equation of metabolism, finally obtaining the every 24 h percentage of various parameters in wine fermentation process.With every 24 h time determination of the change of various metabolic flux showed the trend, found that the direction of some reactions changed in fermentation process, some reactions turned to be reversible reactions;the change of temperature of fermentation and the change of sugar content of fermentation liquor had a significant influence for the growth of yeast and the concentration of organic acid and the reaction rate of metabolic network.