Quality Analysis Of Brown Sugar Vinegar Fermentation And The Monitoring Of Electronic Tongue In Fermentation Process

Brown sugar rich in nutrition is sugar cane or beet juice treated with lime and directly cooked without separating treatment.At present,the development and utilization of brown sugar is mainly based on the brown sugar as an accessory processed beverages,candy and other products,so the product is relatively simple.In this study,brown sugar was used as raw material,and liquid deep fermentation was used to make brown sugar vinegar.Vinegar clarification process and brewing process of brown sugar vinegar were optimized,and the dynamic changes of brown sugar vinegar during the whole fermentation process and the changes of antioxidant and organic acid during fermentation were studied.Meanwhile the electronic tongue technology was used to detect and monitor the fermentation process of the brown sugar vinegar,and a neural network model was established.The main conclusions of this paper are as follows:(1)Brown sugar vinegar brewing process: brown sugar solution 12°Bx,0.05% were inoculated wine yeast by submerged fermentation,The liquid deep fermentation produces brown sweeteners with acidity greater than 4.0 g/100 mL,simple operation,short time,high efficiency;Based on the single factor test,the clarification process of brown sugar vinegar was optimized orthogonally.The optimum technological parameter was chitosan addition 1%,5 ? of temperature,10 h of time,the transmittance of brown sugar vinegar reached 89.32%.(2)During the fermentation process of brown sugar vinegar,the color of the alcoholic fermentation stage changed from the dark red of the brown sugar liquor to the bright red of the red sugar liquor,and the process is mainly divided into three stages: 0~24 h,yeast adapted to the environment using a small amount of nutrients to reproduce;24~108 h,alcohol accumulated rapidly and the alcohol level rises to 6%(v/v);108~132 h,in the slow fermentation stage,the yeast used the remaining reducing sugars to continue the accumulation of alcohol until it reached the maximum alcoholicity and did not grow.The acetic acid fermentation stage red slightly,mainly divided into three stages: 0~24 h: acetic acid bacteria adapted to the environment,increased the reproductive cell density for later preparation;24~60 h: in fast accumulation stage of acetic acid,the acetic acid bacteria used alcohol that total acid content increased to 3.89 g/100mL;60~72 h: in the slow fermentation stage of acetic acid,the acetic acid bacteria continued to oxidize using the remaining alcohol until it reached 4.1 g/100 mL,and the acetic fermentation ended.(3)The change of antioxidant brown sugar in fermentation process showed that the brown sugar fermentation stage of product of scavenging DPPH and ABTS free radical scavenging rate and OH clearance rate,total reducing capacity for liquor wine mash,brown sugar brown sugar,brown sugar vinegar.Compared with vinegar and white vinegar,brown sugar fermentation product was significantly higher than the control group and balsamic vinegar.The total polyphenol and total flavonoids in the fermentation process of a downward trend.The total concentrations of total phenols and total flavonoids were significantly positively correlated with DPPH free radical scavenging rate,ABTS free radical scavenging rate,OH free radical scavenging rate,and total reducing power.(4)The changes of organic acids in the fermentation process of brown sugar vinegar showed that 10 kinds of organic acids were detected in brown sugar vinegar.In the brown sugar vinegar fermentation stage,the most significant change is the increase of acetic acid and tartaric acid,the reduces of oxalic acid and succinic acid.Formic acid,malic acid,and ascorbic acid were the main organic acid in brown sugars,obvious changes in brown sugar vinegar fermentation stage.Fumaric acid was not the main organic acids in brown sugar,it was produced by yeast metabolism during the fermentation process.In alcohol stage accumulation of acetate phase decreased due to acetic acid bacteria or by oxidative degradation.The lactic acid and citric acid in the fermentation process were relatively stable.(5)Electronic tongue could detect and monitor the fermentation process in brown sugar vinegar,principal component analysis could distinguish the brown sugar vinegar in the fermentation process of the component change and did not overlap between the components,the pre-fermentation changes than late fermentation changed more obviously.The radar chart showed that the sensor signals of ZZ,JE,and BB changed significantly during alcohol fermentation,and the JE sensor changed most obviously during the fermentation of acetic acid.When the cluster analysis showed that the similarity during the fermentation process was25,the alcohol fermentation process and the acetic acid fermentation process could be divided into the adaptation stage and the fermentation stage of the alcohol or acetic acid fermentation process.Reducing sugar and pH on ethanol fermentation stage,BP neural network model was established by acetic acid fermentation stage of total acid and pH,the results showed that the regression of reducing sugar and pH correlation coefficient of prediction value and the actual value were 0.989 and 0.985,total acid and pH regression prediction correlation coefficient value and the actual value were 0.966 and 0.990.