窖池中酸性脲酶产生菌的分离鉴定及其对模拟窖泥pH值和风味物质的影响OA北大核心CSTPCD

In order to alleviate the aging phenomenon of Baijiu cellar pits,acid urease producing bacteria were isolated from pit mud of Sichuan Swellfun Co.,Ltd.The isolated strain was mixed with Clostridium kluyveri S008 for solid-state fermentation to investigate the effect of acid urease producing bacteria on the pH value and volatile flavor compounds of simulated pit mud.The results showed that a total of 4 strains of acid urease producing bacteria were screened and identified,named as Lactobacillus buchneri S162,Staphylococcus cohnii S163,Rummeliibacillus pycnus S164,and Rummeliibacillus suwonensis S165.The urease activities of the four strains were ranged from 0.45 to 1.51 U/mL.These four strains could raise the pH of pit mud models.The pH value of the simulated pit mud showed a trend of up-per＞middle＞lower,with the highest pH value observed for S163 group(P＜0.05).Among the flavor substances analyzed,S163+S008 group had the highest acetaldehyde content(2.38 mg/100 mL),while S162+S008 group had the highest aldehyde acetal content(2.50 mg/100 mL);The content of n-propanol,n-butanol,n-hexanol,and isoamyl alcohol after co-fermentation were 1.41-1.97 times,0.92-1.85 times,0.66-1.58 times,and 1.13-1.69 times higher than that of single fermentation group,respectively.The synergistic fermentation of S164 and S008 showed the most significant increase in caproic acid content(P＜0.05).The synergistic fermentation of four strains of bacteria with S008 could increase the content of"four major esters"by 2.66-5.02 times,1.21-4.85 times,1.33-3.31 times,and 1.27-2.86 times,respectively.The present study showed that the synergistic fermentation of these four acid urease pro-ducing strains with Clostridium kluyveri S008 could increase the pH and the production of major volatile flavor compounds in pit mud models.