Condition Optimization And Fermentation Kinetics Analysis Of Solid State Reactor For Vinegar

China’s vinegar brewing has a long history.Shanxi aged vinegar,Zhenjiang vinegar and other famous vinegars in my country are produced by solid-state fermentation process.The products have unique flavor and are deeply loved by consumers.The production of traditional vinegar is currently manual or semi-mechanical.The labor demand is high and the working environment is poor.It is urgent to improve the modernization level and promote the highquality development of the industry.The application of vinegar solid-state fermentation tank is an effective way to improve the current situation of the vinegar industry,but the current production process of vinegar solid-state fermentation tank is still immature,and there are problems such as unstable fermentation process and poor product flavor.This paper analyzes and optimizes the main parameters affecting the application effect of the drum-type vinegar solid-state fermentation tank,and provides experience and guidance for its further popularization and application,which has important application value.The method of satisfaction function was adopted,and the utilization rate of raw materials and flavor substances in the fermentation process were comprehensively considered.Single factor analysis was carried out on the operating parameters such as the temperature of the Rotating drum bioreactor,the aeration agitation cycle,the ventilation time,the amount of inoculum,the charging amount,and the stirring speed.According to the univariate analysis results,the Plackett-Burman factor level was selected,and the PlackettBurman design experiment was carried out to obtain the model F value and P value of 17.75 and 0.0031,respectively.The contribution of the three parameters to the vinegar fermented grains score was 49.13 %,22.41 % and 15.94 %.According to the Cupei of the temperature of the fermentation process of traditional vinegar fermentation,the aeration agitation cycle and temperature were regulated in stages.For the aeration agitation cycle,it is better to adopt the cycle of 8 h in the first and middle stage,4 h in the later stage.The temperature was fluctuated and increased in the early stage,increased by 4 °C in the rising stage,decreased by 2 °C in the descending stage,and reached a maximum temperature of 42 °C on the 5th day;in the middle stage,the cooling temperature dropped to 34 °C by 2 °C per day;in the later stage,the fermentation was maintained at a constant temperature of 34 °C.Under this control condition,the highest Dv value of vinegar grains was 0.66,the raw material utilization rate was 15.94 %,and the fermentation period was 15 d.Finally,the kinetic analysis of the bacterial growth,product generation and substrate consumption of acetic acid bacteria and lactic acid bacteria during acetic acid fermentation in a drum reactor was carried out,using the Logistic model,the Luedeking-Piret model and the Luedeking-Piret/Like model.The maximum colony number and maximum acetic acid concentration of acetic acid bacteria were 3.712*106 CFU/g Cupei and 5.348 g/100 g Cupei,respectively,which were 0.32% and 0.003% different from the measured values.The maximum bacterial cell concentration and maximum lactic acid concentration of lactic acid bacteria were 4.416*105 CFU/g Cupei and 2.457 g/100 g Cupei,which were 1.36% and 0.66%different from the actual measured values,respectively.Therefore,the kinetic equation can well characterize the fermentation state of acetic acid bacteria and lactic acid bacteria,and provide a useful prediction of.fermentation trend.