苗族白酸汤中优势乳酸菌及酵母菌的筛选与应用

Screening and Application of Dominant Lactic Acid Bacteria and Yeasts in Rice Sour Soup from Miao

目的:为了得到适合白酸汤发酵的发酵剂,实现传统白酸汤的规范性生产。方法:采用溶钙圈法结合总酸产量和耐酸耐胆盐实验筛选乳酸菌优良菌株;采用糖苷酶活性实验筛选酵母菌优良菌株;通过生理生化实验、16S rDNA序列和ITS序列进行菌株鉴定。将两株优良发酵菌株复配应用于白酸汤中,对其pH、总酸、总糖、还原糖和感官品质进行分析。结果:从128株乳酸菌中筛选出1株产酸能力较强的菌株G1-3,该菌株在pH3.0与0.3%牛胆盐环境中均生长良好,从20株酵母菌中筛选出1株糖苷酶活性较强的菌株G2-2。经鉴定菌株G1-3为副干酪乳酸杆菌(Lactobacillus paracasei),G2-2为印迪卡有孢圆酵母(Torulaspora indica)。两株菌复配发酵后的籼米白酸汤的总酸含量较自然发酵提高了5倍,总糖与还原糖含量分别降低了61.53%与81.02%;糯米白酸汤中的总酸含量较自然发酵提高了18倍,总糖与还原糖含量分别降低了68.86%与86.99%。两株菌复配发酵后的白酸汤的感官品质也优于自然发酵。结论:G1-3与G2-2的复合发酵剂发酵得到的白酸汤具有较好的品质,有望应用于白酸汤的发酵生产。

Objective:To obtain the starter culture suitable for rice sour soup fermentation,and realize the standard production of traditional rice sour soup.Methods:The excellent strains of lactic acid bacteria were screened by calcium-dissolving circle method combined with total acid yield and the tolerance experiments of acid and bile salt;The experiment of glycosidase activity was used to screen the excellent strains of yeast.The strains were identified by physiological and biochemical experiments,16S rDNA and ITS sequence;The compounded two excellent fermentation strains were applied to rice sour soup,and their pH,total acid,total sugar,reducing sugar and sensory quality were analyzed.Results:The strain G1-3 with strong acid-producing ability was selected from 128 strains of lactic acid bacteria,which grew well in the environment of pH3.0 and 0.3%bovine bile salt.The strain G2-2 with strong glycosidase activity was screened from 20 yeasts.The strains G1-3 and G2-2 were identified as Lactobacillus paracasei and Torulaspora indica,respectively.Compared with natural fermentation,the total acid content of indica white sour soup fermented by two strains of bacteria increased by 5 times,while the total sugar and reducing sugar content decreased by 61.53%and 81.02%,respectively;The total acid content in glutinous rice sour soup increased by 18 times,while the content of total sugar and reducing sugar decreased by 68.86%and 86.99%,respectively.Also,the sensory quality of white sour soup fermented by two strains of bacteria was better than that of natural fermentation.Conclusion:The white sour soup fermented by compound starter of G1-3 and G2-2 has excellent quality,which is expected to be applied to the fermentation production of white sour soup.