Study On The Color Change And Coloration Mechanism By Yeast And Pyruvic Acid During The Wine Fermentation

Anthocyanin is a water-soluble pigment that determines the color of fruit wine.The metabolite(pyruvic acid)during yeast fermentation can affect the structural transformation of anthocyanins.In this study,the content of anthocyanin degradation products and derivatives was analyzed by constructing a fruit wine simulation fermentation system after adding Cyanidin-3-O-glucoside(C3G)in fruit wine.The color index of the solution was analyzed and the reasons for the color change of the wine were explained.Finally,the complete mechanism of the influence of yeast on the anthocyanins was illustrated.According to the actual production of fruit wine fermentation conditions,various auxiliary factors suitable for yeast growth were added,sugar content and p H value were adjusted to construct a simulated fermentation broth of fruit wine and to construct a fermentation system of simulated fruit wine.Determined the CIELAB color parameters of the simulated fermentation broth,analyzed the color change phenomenon during the fermentation process,and explored the cause of the color change by pyruvic acid during the fruit wine fermentation process.Used ultra performance liquid chromatography-mass spectrometry(UPLC-MS)to qualitatively and quantitatively analyze the anthocyanin,anthocyanin degradation products and anthocyanin derivative products during the fermentation process,and obtained the dynamic changes of anthocyanin,anthocyanin degradation products and anthocyanin derivative products.Using non-targeted metabolomics to analyze the differential metabolites in the fermentation process,the main degradation and derivatization pathways of anthocyanins in the yeast fermentation process were analyzed.In the case of yeast participation,the chromaticity of the solution was significantly reduced;and yeast under the condition of pyruvic acid stress,the chromaticity of the solution decreased most significantly.RC212 yeast significantly increased the L*,h_ab,and?E values of the solution,and significantly reduced the a^*,b^*,and C^* values of the solution;When pyruvic acid was involved,the h_ab and?E values of RC212 yeast fermentation broth significantly increased,and the a^*and C^*values significantly decreased.The main products of anthocyanins in the yeast fermentation process are Cyanidin,Vitisin B,protocatechuic acid,and 2,4,6-trihydroxybenzaldehyde.In the early stage of fermentation,pyruvic acid will significantly reduce the content of C3G and Cyanidin in the solution.However,there was no significant change in the contents of Vitisin B,Protocatechuic acid and 2,4,6-trihydroxybenzaldehyde in the solution.The structure transformation pathway of anthocyanins was obtained by using non-targeted metabolomics.On the one hand,with the participation of yeast,the glucosyl group of anthocyanins undergoes condensation reaction with pyruvic acid to produce Cyanidin-3-O-(3'-malonyl)glucoside;On the other hand,anthocyanins are degraded to produce cyanidin aglycone,and the aglycone is isomerized to produce Vitisin B,Fisetin,Taxifolin and Kaempferol.Kaempferol reacts with glucose and galactose in the solution to produce Kaempferol-3-O-glucose,Kaempferol-7-O-glucose and Kaempferol-3-O-galactose.Pyruvic acid can significantly increase the content of Cyanidin-3-O-(3'-malonyl)glucoside,Kaempferol-3-O-glucose,Kaempferol-7-O-glucose and Kaempferol-3-O-galactose.The main reason for the significantly low chroma under the condition of pyruvic acid stress is the decrease of C3G and Cyanidin.Pyruvic acid accelerates the deglycosidization of C3G,which leads to degradation and derivatization reactions.As a result,the content of C3G and Cyanidin is significantly reduced,and the color of the solution is reduced.