Metabolomics Analysis of Fermentation Characteristics of Lactococcus lactis subsp. lactis in Soymilk

Most current studies on Lactococcus lactis subsp. lactis are focused on its application in bovine milk, but few studies have been conducted on its application in soymilk. The fermentation characteristics of Lactococcus lactis subsp. lactis in soymilk were analyzed by metabolomics and sensory evaluation in the present study. The results showed that Lactococcus lactis subsp. lactis strains DYNDL21-2, DYNDL1-2 and FJNDD18M8 showed good sucrose metabolism capacity, growth and acid production ability. The abundance of hexanal and various heterocyclic compounds such as furan in fermented soymilk was significantly down-regulated by DYNDL21-2 and FJNDD18M8, which effectively reduced the intensity of beany odor. Fermentation with FJNDD18M8 significantly up-regulated the abundance of acetaldehyde, acetoin and 2,3-butanedione in soymilk, enhancing the milky aroma and creamy flavor and improving the overall flavor. In conclusion, Lactococcus lactis subsp. lactis has excellent fermentation characteristics and strong metabolic capacity during soymilk fermentation, but there are some differences among strains.