The former four conditions within the non-post fermented Shuidouchi formed a superimposed inhibitory influence on the fungi, on the molds especially. Food given birth to biogenic amines contain nitrogenous chemical substances that result from proteins from microbial decarboxylation, and eight biogenic amines are located often. the prosperity from the spore-producing bacterias such as for example (a lot more than 90% comparative abundance Litronesib Racemate in bacterias) and (2% roughly comparative abundance in bacterias), as well as the inhibition of fungi. Furthermore, it had been found by relationship analysis which the comparative abundances of and had been favorably correlated with the comparative articles of amino acidity fat burning capacity pathway and this content of all alkylpyrazines and biogenic amines. On the other hand, the comparative abundances of several nondominant bacterias had been adversely correlated with this content of biogenic amines and favorably correlated with the comparative articles of carbohydrate fat burning capacity pathway. These results had been beneficial to control the biogenic amine items under the basic safety limits, raising the alkylpyrazine type and item functionality. A two-stage heat control strategya moderate heat (35C42C) first, then a high temperature (52C)was concluded from the spontaneous fermentation of non-post fermented Shuidouchi. This strategy could improve the safety of product by inhibiting or sterilizing the thermolabile microbes. The non-post fermented Shuidouchi product is usually rich in functional compounds such as polyamines and alkylpyrazines. anticancer, and antimutagenic effects (6). Because non-post fermented Shuidouchi has shown vascular protective and anti-hypertension functionality (7, 8), as well as a high activity of fibrinolytic enzymes (9), with lower salt content, a shorter processing cycle, and a lower cost, it has drawn increasing attention from researchers and enterprises. Although the fermentation process of non-post fermentation Shuidouchi is usually relatively short (48C72 h), various microorganisms secrete a variety of enzymes in the product that will promote the hydrolysis of soybeans and the generation of various metabolites, resulting in the appearance of a brown mucous, a Douchi smell, and a spontaneous increase in heat. Previous research has focused on comparative studies of bacterial diversity in the initial and final stages of Shuidouchi (10) and the microbial diversity of products from different regions (11). However, there is still a lack of detailed research on the relationship of microbes and functional metabolites during the fermentation of non-post fermented Shuidouchi. Recently, the high-throughput nucleotide sequencing technique was applied to analyze the microbial diversity in many foods, as it can identify unculturable microbes (11C14). However, the culture-dependent method should also be used to investigate the microbial ecology for more accurate results. A variety of physiologically active substances such as biogenic amines (BAs) were found to generate during the fermentation of non-post fermented Shuidouchi, among which polyamines were found to exhibit protective effects against chronic diseases (15, 16). In recent years, studies have found that the content of certain BAs reached or approached harmful levels in commercial Natto and Shuidouchi products. Certain Litronesib Racemate strains in Natto were found to accumulate high concentrations of -phenylethylamine and tyramine, which could cause food safety problems; thus, BAs must be monitored during fermentation (16, 17). In addition, other physiologically active substances such as alkylpyrazines were also found in fermented soybean products. Among the alkylpyrazines, 2,3,5,6-tetramethylpyrazine (tetramethylpyrazine) has been shown to promote human cardiovascular and cerebrovascular health (18C20), increase immune organ indices and natural immunoglobulins (21), relieve symptoms of animal experimental autoimmune myasthenia gravis (22), and protect against acute alcoholic liver injury (23). Tetramethylpyrazine has also been found MGC20372 in mold type Douchi Litronesib Racemate (24, 25). These metabolites were shown to be related to the population changes and physiological metabolic pathways of microbes during fermentation. However, the correlation between microbes and alkylpyrazines in Douchi (including non-post fermented Shuidouchi) remains unknown. Thus, an investigation into the relationship of functional compounds and microbial metabolism pathways in Douchi is needed. This research explored the microbial community structure of non-post fermented Shuidouchi, and its associations with Litronesib Racemate both the functional metabolites and microbial metabolism pathways, to provide information for optimizing the safe and functional qualities of this product. Materials and Methods Chemicals and Materials The study material consisted of yellow soybeans [(Linn.) Merr.], which were purchased from a market in Yantai city, Shandong province, China. BAs or amine hydrochlorides, such as histamine (HIS), -phenylethylamine (PHE), Tryptamine (TRP), cadaverine dihydrochloride (CAD), putrescine dihydrochloride (PUT), tyramine hydrochloride (TYR), spermine (SPM), and spermidine (SPD), were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China), with purities of 98%. Acetone and acetonitrile were of HPLC grade, while the other chemicals were analytically real. All chemicals were purchased from Sinopharm Group Co., Ltd. (Beijing, China), and the plate count agar (PCA, CM101), De Man Rogosa Sharpe agar (MRSA, CM188), Manitol salt agar (MSA, CP813), brain heart infusion agar (BHIA, CM918), potato dextrose agar (PDA, CM123, and yeast extract glucose chloramphenicol agar (YGC, CM840) were purchased from Land Bridge Technology Co., Ltd. (Beijing, China). Bacterial and yeast genome extraction kits and lyticase were purchased from Tiangen Biotech Co., Ltd. (Beijing,.