Optimization Of Acetic Acid Fermentation Process And Research On Main Ingredients Of Lycium Barbarum Vinegar

Lycium barbarum is a kind of precious Chinese herbal medicine with the same origin as medicine and food.It contains rich nutritional active ingredients and has high value of medical care.At present,Lycium barbarum is mainly based on primary processing,and the development of deep processing products is insufficient.The Lycium barbarum is fermented and brewed into vinegar,which can not only make full use of wolfberry resources,broaden its deep processing forms,but also enrich fruit vinegar products.In this study,we used fresh Lycium barbarum juice as raw material to optimized the fermentation process conditions of Lycium barbarum acetic acid,and measured and analyzed the main ingredients and antioxidant activities of Lycium barbarum vinegar in the fermentation process,and the specific research results are as follows:Firstly,the acid production rate was used as an index to conduct single factor experiments on the initial alcohol content,initial acidity and inoculation amount.And the optimal level of single factor was optimized by response surface methodology.The results showed that the optimal technological conditions of acetic acid fermentation of Lycium barbarum vinegar were as follows: initial alcohol content 8.60%vol,initial acidity 1.10 g/100 m L and inoculation amount 9.70%.Under these conditions,Acid production rate was 0.87 g/L/h.Secondly,the main flavor substances in the fermentation process of Lycium barbarum vinegar were determined by headspace solid phase microextraction-gas chromatography-mass spectrometry,amino acid analyzer and liquid chromatography.The results showed that a total of 94 volatile ingredients(acids,esters,alcohols,aldehydes and ketones,etc.),15 kinds of amino acids(sweet amino acids,bitter amino acids and umami amino acids,etc.)and 9 kinds of organic acids(citric acid,malic acid,lactic acid and acetic acid,etc.)were detected during the fermentation process of Lycium barbarum vinegar.Finally,the main functional ingredients and antioxidant activities in the fermentation process of Lycium barbarum vinegar were determined.The polysaccharide content measured by phenol sulfuric acid method can reach 8.94 mg/m L,which is the main active ingredient in the fermentation process of Lycium barbarum vinegar.And 18 kinds of polyphenols were detected by gas chromatography-mass spectrometry.The antioxidant activity of goji berry vinegar in the fermentation process was measured by DPPH method,FRAP method and ABTS method.The results showed that the antioxidant activity in the fermentation process showed a trend of first decreasing and then increasing,and the antioxidant activity of Lycium barbarum vinegar was higher than that of Lycium barbarum juice and Lycium barbarum wine.In addition,the correlation between functional ingredients and antioxidant activity during fermentation was evaluated,and the results showed a significant positive correlation between polysaccharide,betaine,total phenol and total flavonoid content and antioxidant activity.The results of this study indicate that the fermentation process of g Lycium barbarum vinegar is rich in a variety of flavor substances and nutrient active ingredients,and has high antioxidant activity.The results provide a theoretical and applied basis for enriching the deep processing forms of Lycium barbarum and the development of fruit vinegar products.