Unravelling the correlations among the microbial community, physicochemical properties, and volatile compounds of traditional mung bean sour liquid

Sour liquid noodles are a characteristic traditional food in Luoyang, China. Mung bean sour liquid (MBSL) is fermented from mung beans and used to cook noodles (instead of using water). However, the microbial community, volatile compounds, and physicochemical properties of MBSL are still unclear. Here, a comprehensive study was conducted using a combination of Illumina HiSeq sequencing, gas chromatography‒mass spectrometry detection, and physicochemical analysis methods. Eight phyla and 59 genera of bacteria were identified in MBSL, of which 4 genera were dominant, namely, Lactobacillus, Lactococcus, Leuconostoc, and Lelliottia. Six phyla and 123 genera of fungi were detected, with 11 genera being dominant. The protein content, total acid content, and pH mainly influenced the microbial community. Myroides, Aeromonas, Flavobacterium, and Lactobacillus, etc. May play important roles in balancing MBSL ecosystems. There were 40 volatile compounds in MBSL, with 1-hexanol, eugenol, acetic acid, and hexanoic acid being considered key volatile compounds. Lactobacillus, Algoriella, Lelliottia, and Leuconostoc were significantly correlated with the volatile compounds found in MBSL. The complex correlation between microbial communities, volatile compounds, and physicochemical properties may be elucidated through these findings. Controlling environmental factors and increasing the number of selected microbial cultures may improve the quality of MBSL.