Preparation And Application Of Highly Efficient Leavening Agent Of Traditional Vinegar

Lactic acid bacteria was main microorganisms to produce the flavor substances such as lactic acid during the fermentation process of vinegar which has a significant influence on the entire traditional vinegar.Lactic acid bacteria with good fermentation property was mainly separated and screened from traditional vinegar pei,and was prepared to agent,and then its actual application on the fermentation process of tianjin duliu vinegar was analyzed and studied in this paper in order to lay a basis for controlling the fermentation process of traditional vinegar.The growth,acid production,acid resistance,heat resistance and polysaccharide of lactic acid bacteria isolated from vinegar pei were analyzed and compared,the lactic acid bacteria AAF1-5 strain with excellent fermentation property was obtained and by 16S r DNA identified as Pediococcus acidilactici.This strain perform better growth and metabolic activity under conditions of 45? and pH4.0,and its exopolysaccharide has good antioxidant activity.The fermentation medium of Pediococcus acidilaclici was optimized,and the consist of the optimal fermentation medium was:glucose 2.0%,peptone 1.0%,beef extract 1.0%,yeast extract 0.5%,NaAc 0.5%,K2HPO4 0.2%,MgSO4 0.058%,malt wort 20%.Compared with non-optimized medium,the highest number of viable cells was(3.96±6.01)×109 CFU/mL under optimized medium.The agent of Pediococcus acidilactici was prepared.Under the condition of vacuum freeze drying and lactose as protecting agent,the number of survival cells was(5.66±0.07)×1010 CFU/g,the survival rate of cells was 87.5%.And the stability of agent was studied,the results showed that the best preservation time was 3 months,under this condition,the survival rate of cells achieve the level more than 80.3%.The agent was actually applied to the fermentation process of Tianjin duliu vinegar,adding agent during the fermentation stage of acetic acid,the addition of agent was 1010 CFU/vat.Compared with the control,the fermentation period of vinegar is shortened to 4 days.Vinegar pei was analyzed after the period of acetic acid fermentation,compared with the control group,the organic acids was 8.5±0.1 g/100g,increase by 8.9%,the content of lactic acid was 3.1±0.2 g/100g,increase by 14.8%,the content of acetic acid was 5.3±0.2 g/100g,increase by 6.0%.PCR-DGGE method was used to analyze the bacterial community of above and below during fermentation process.Results showed that P.acidilactici detected in fermentation process of add agent,but others was not detected.Canonical correspondence analysis(CCA)was employed to analyze the relationship between bacterial community and organic acids.Results showed that the upper pei of bacteria which contribute to lactic acid formation were L.plantarum>P.acidilactici>L.panis>L.frumenti>L.vaginalis,but the below pei of bacteria which contribute to the content of lactic acid formation were P.acidilactici>L.crispatus.The results indicated that addiing agent could promote the synthesis of organic acids such as lactic acid during the vinegar fermentation of Tianjin.According to GB/T 19461-2008<Geography Signs Products Duliu Vinegar>total acid 3.5g/100mL was taken as criteria to adjust.The vinegar ingredients were compared and analyzed for each group.The results showed that compared with the control group non-volatile acid,amino-N,reducing sugar,total organic acid and total amino acid,increased by 52.1%,32.3%,34.5%,5.8%and 17.6%,respectively.Specially speaking,the lactic acid increased 12.2%;lactic acid/acetic acid increased 13.1%.The results of Prineipal component analysis(PCA)was shown that agent has significant positive correlation with organic acids and amino acids of vinegar.According to all results,addition of agents not only increase the content of correlated components,also improve the flavor of vinegar.