Microbial community structure of lactic acid bacteria in Shanxi aged vinegar production and the flavor metabolism characteristics of superior strains

The structure of lactic acid bacteria in Daqu, fermented mash and Cupei of Shanxi aged vinegar was analyzed by Illumina Miseq highthroughput sequencing technology and traditional cultivable technology, and the lactic acid bacteria strains with excellent acid production ability were isolated and screened through traditional culture separation technology. The flavor metabolism characteristics in different simulated media were analyzed by HPLC and HS-SPME-GC-MS. The results showed that the main lactic acid bacteria genera in Daqu were Lactobacillus and Pediococcus, and the main lactic acid bacteria genera in the alcohol and acetic acid fermentation stages were Weissella, Lactobacillus and Pediococcus. A total of 10 strains of excellent lactic acid bacteria with high acid production [total acid(8.26-24.30 g/L)and non-volatile acid(5.60-15.3 g/L)] were screened. After identification, 4 strains were Lactiplantibacillus plantarum and 2 strains were Lactobacillus brevis, 2 strains were Pediococcus pentosaceus, 1 strain was Pediococcus acidilactici, and 1 strain was Enterococcus durable. The total organic acids and lactic acid contents of 10 strains of lactic acid bacteria were higher in MRS liquid medium and simulated Cupei medium. A total of 100 volatile flavor components were detected from the 4 simulated media, the total contents of volatile flavor compounds produced by the strains were higher in barley pea medium and simulated Cupei medium (except for P. acidilactici L729). Among them, L.plantarum L19 had excellent flavor metabolism characteristics.