豉香型白酒醪液源耐酸乳杆菌La50发酵特性研究

Fermentation characteristics of Lactobacillus acetotolerans La50 from mash in Chi-flavor Baijiu production

该研究以分离自豉香型白酒醪液中的耐酸乳杆菌(Lactobacillus acetotolerans)La50为研究对象,对其生长特性、产酸能力及耐受性进行分析,并将其应用于豉香型白酒发酵,对其发酵特性进行研究。结果表明,耐酸乳杆菌La50生长旺盛,对数期(2~38 h)较长,最适生长温度为37℃、最适生长p H为5;可耐受pH值3.0、7%NaCl和42℃的高温环境,具有较好的环境耐受性;其在改良MRS液体培养基中37℃发酵72 h时,总酸含量为18.49 g/L,具有较好的产酸能力;其发酵液中乳酸含量最高[(19.14±0.36)g/L],其次是乙酸[(4.08±0.24)g/L]和苹果酸[(2.87±0.13)g/L],柠檬酸和琥珀酸未检出。通过模拟酿酒发酵试验发现,与对照组相比,试验组模拟发酵酒样中总酸、总酯和乳酸含量分别提高74.47%、189.19%和179.23%;挥发性风味物质总含量提高,其中酯类物质和醇类物质分别提高311%、13.94%,且乙酸乙酯含量提升最明显,提高81.88%。此外,仅在试验组模拟发酵酒样中检测出乙酸己酯、辛二酸二乙酯和醋酸。综上,该菌株有作为发酵菌剂提升豉香型白酒风味和口感的潜在应用价值。

Using Lactobacillus acetotolerans La50 isolated from mash in Chi-flavor Baijiu production as the research object,its growth characteristics,acid production capacity and tolerance were analyzed.It was applied to Chi-flavor Baijiu fermentation,and the fermentation characteristics were studied.The results showed that L.acetotolerans La50 grew strongly,with a longer logarithmic phase(2-38 h),the optimal growth temperature was 37℃,and the optimal growth pH was 5.It could tolerate pH 3.0,7%NaCl,and 42℃high temperature environment,which had a good environmental tolerance.The total acid content was 18.49 g/L after fermentation at 37℃for 72 h in modified MRS broth medium,which showed good acid-producing capacity.The lactic acid content in the fermentation broth was the highest[(19.14±0.36)g/L],followed by acetic acid[(4.08±0.24)g/L]and malic acid[(2.87±0.13)g/L],citric acid and succinic acid were not detected.The simulated brewing fermentation experiments showed that compared with the control group,the contents of total acid,total ester and lactic acid in the experimental group of simulated liquor samples were increased by 74.47%,189.19%and 179.23%,respectively.The total content of volatile flavor compounds increased,among them,the contents of esters and alcohols were increased by 311%and 13.94%,respectively,and the ethyl acetate content increased most significantly,which increased by 81.88%.In addition,hexyl acetate,diethyl octanoate,and acetic acid were detected only in the simulated fermented liquor samples of the experimental group.In conclusion,the strain had potential application value as a fermentation starter to enhance the flavor and taste of the Chi-flavor Baijiu.