Optimization Of Loquat Vinegar Fermentation Processing Parameters

During the alcohol fermentation and acetic acid fermentation,the main process parameters of Dawuxing Loquat(Eriobotrya japonica(Thunb.)Lindl.)were optimized by the liquid fermentation technology.By clarification and formula experiment,this study produced a Dawuxing Loquat vinegar with refreshing taste and sour soft.The followings are the main results:1.Taking the final alcohol as an index,the orthogonal test based on single factor experiment to determine the optimum alcoholic fermentation conditions:temperature 30℃,initial pH3.5,0.6%inoculation amount and initial TSS content 15°Brix.The best prediction formula between the alcohol and content of TSS is:y = 0.0116x3-0.5955x2-50.631 x + 10.235,the correlation coefficient R2= 0.9893,Chi2= 0.00585<0.05.This prediction formula can indicate the alcohol changes effectively.2.Through single factor and orthogonal experiment,this study tested the content of acetic acid during the fermentation liquid.The best parameters of acetic acid fermentation were optimized:initial pH4.0,temperature 32 ℃,15%inoculation amount,initial alcohol content 8%.Within these conditions,the Loquat vinegar’s final acidity was 4.79±0.05g/100mL,the conversion of acetic acid is 59.86%,the content of TSS is 6.1 °Brix,the content of reducing sugar was 1.12g/100g.3.The kinetic model of acetic acid producing is fitted by Logistic model:y=-4.8499/1+(x/2.21096)3.60723+4.92585,Chi2=0.00786,R2=0.99691,4.Taking the 600 nm’s light transmittance as an index,this study determine the optimum parameters of chitosan,diatomite and gelatin by the single factor experiment.The best clarification parameters were:0.5%chitosan concentration;0.4%diatomite;0.08%gelatin amount.The results also indicated that 0.4%diatomite had the fastest clarify rate,while the 0.5%chitosan had the best clarification effect.5.Taking the loquat juice,vinegar content,white sugar,citric acid as four factors of Dawuxing Loquat vinegar beverage’s sensory indexes,this study determined:loquat vinegar 8 mL/100mL,sugar 9g/100mL,citric acid 125mg/100mL,loquat juice 7.5 mL/100mL.6.After the former optimization,the loquat vinegar product was yellow,s hiny,with classic vinegar flavor and no odor.The total acidity is 0.42g/100mL,the content of TSS is 15.4°Brix,the content of reducing sugar was 12.28g/1 OOg.The total number of bacteria is<100 CFU/mL,and the munber of Esch erichia coli is≤ 3 MPN/100mL.The pathogenic bacteria were not detected.Th e quality meet the standard of GB 7101-2015.