Microbiome Flora and Metabolomics Analysis of Mung Bean Sour Liquid in Luoyang, China

In order to reveal the fermentation microflora and fermentation metabolites of traditional mung bean sour liquid (MBSL) in Luoyang area, China, this experiment was sampled from four administrative districts of Luoyang, and volatile metabolites and non-targeted metabolites were detected and analyzed by HS-SPME-GC-MS and LC-MS, and bacterial and fungal sequencing were analyzed by Illumina MiSeq high-throughput sequencing technology. And the correlation between microorganisms and metabolites was conducted. The results showed that 42 volatiles were detected in four MBSL samples named Jianxi (JX), Liujia (Liu), LiJia (LJ), Majia (MJ), with 11 identical volatile flavor subtances, and the highest content of esters was found in JX, Liu, and LJ, and the highest content of acids was found in MJ. A total of 1703 non-targeted metabolites were identified, and there were more types of amino acids, carbohydrates, fatty acids and their complexes, flavonoids, carbonyl compounds, and organic acids, accounting for 40.93%. High-throughput sequencing results showed that there were nine bacterial and fungal genera with an average abundance of more than 1%, and the dominant genera mainly belonged to lactic acid bacteria and yeast. The composition of dominant genera was different in different workshop samples, and the abundance of fungal genera differed greatly. Among the volatile substances, Methyleugenol, a volatile component, was related to more bacteria, and ketones and hydrocarbons may be more closely associated with bacteria. Acetic acid and Oxalic acid may be more closely related to fungi, while some esters were more closely related to both fungal and bacterial genera. For non-target metabolites, amino acid and alcohol metabolites may be more influenced by bacteria, and organic acids and flavonoids may be more influenced by fungi.