Process Optimization And Composition Analysis Of Ice Vinegar

The public's demand for ice wine has led to the development of ice wine industry,resulting in a large number of ice grape peel as waste resources.Ice grape peel residue is a by-product of ice wine.It contains sugar and functional substances.It is usually used as feed or fertilizer nowadays while most of its value is undeveloped.To improve ice grape peel's use value,this experiment used ice grape peel residue as the raw material for fermentation,cooperating with grapes to brew grape vinegar.Optimizing technological parameters of ethanol and acetic acid fermentation of ice grape vinegar by orthogonal design and response surface methodology.The results showed that pectolase could maximize the sugar content of fermentation broth when the enzymatic hydrolysis time was 1.5 h,the enzymatic hydrolysis temperature was 55? and the addition amount was 0.3 %;The optimum technological parameters of alcohol fermentation are 200 m L/250 m L bottle quantity,5 % inoculation quantity,fermentation for 7 days at 20?.Design-Expert 10 software was used to fit the experimental parameters of response surface methodology by regression equation,and finally the research conditions of the optimal fermentation were obtained:inoculum 15 %;fermentation temperature 28°C,initial alcohol 7.0 %.Semi-continuous fermentation is adopted,and the vinegar efficiency is the highest,When the amount of division is 60%.When the temperature was 28?,4% clarifying agent was added and clarified for 3 hours,the light transmittance was the highest.After the optimization of the process,the contents of vitamin C,total flavonoids,total polyphenols,proanthocyanidins and oleanolic acid in ice grape vinegar were 16.47 mg/L,44.55 mg/L,20.06 mg/L,24.78 mg/L and 112.49 mg/L.Ice grape vinegar has a strong antioxidant effect,inhibits the activity of alpha-glucosidase,has a certain hypoglycemic effect,and has a certain inhibitory effect on cholesterol.In conclusion,the research on the brewing technology of ice grape vinegar provides a technical basis for the reuse of resources and the enrichment of grape vinegar varieties.