Traditional fermented soybean food has emerged as an important part of people's dietary structure because of the unique flavors and improved health benefit. During fermentation, the nutrients in soybean undergo a series of biochemical reactions catalyzed naturally by microorganism secreted enzymes. Thereafter, many functional and bioactive substances such as bioactive peptides, unsaturated fatty acids, free soy isoflavones, vitamins and minerals are produced, making fermented soy products more advantageous in nutrition and health. This review comprehensively discusses the historical evolution, distribution, traditional fermentation processing, main sources and characteristics of fermented strains, flavor components, nutritional properties, and biological activities of four traditional fermented soybean foods including douchi, sufu, dajiang, and soy sauce. In the end, we introduce four major challenges encountered by traditional fermented soybean foods including high salt content, formation of biogenic amine, the presence of pathogenic microorganisms and mycotoxins, and quality inconsistency. We conclude that the establishment of scientific quality standard and innovated fermentation processing is the potential solutions to combat the issues and improve the safety of traditional fermented soybean products.

Traditional fermented soybean products: processing, flavor formation, nutritional and biological activities.

Correlation between autochthonous microbial communities and key odorants during the fermentation of red pepper (Capsicum annuum L.).

Analyses of microbial community of naturally homemade soybean pastes in Liaoning Province of China by Illumina Miseq Sequencing.

This study was conducted to screen the lactic acid bacteria (LAB) with admirable technological properties and high protease activity from traditional Chinese fermented sausages, and to investigate the effects of LAB on the antioxidant activity of peptides of fermented sausages. Seven strains were obtained from 133 LAB isolates. They complied with the criteria of meat starter cultures with high proteolytic activity. These strains were analyzed by API and sequence analysis of 16S rRNA to identify the five strains of Lactobacillus plantarum, one strain of L. fermentum, and one strain of L. pentosus. Furthermore, L. plantarum CD101 was inoculated with fermented sausages. LC-MS/MS was used to analyze the peptide composition. Compared with control group, using L. plantarum CD101 as starter cultures (Group L) led to a significant increase (P < 0.05) in antioxidant activity. The relative content of most peptides in Group L samples was largely higher than that in control samples.

https://tandfonline.com/doi/pdf/10.1080/19476337.2019.1583687

Screening of lactic acid bacteria with high protease activity from fermented sausages and antioxidant activity assessment of its fermented sausages

Smartphone-based competitive immunoassay for quantitative on-site detection of meat adulteration

Effects of replacing fat with Perilla seed on the characteristics of meatballs.

Exploring the bacterial community for starters in traditional high-salt fermented Chinese fish (Suanyu).

Nattokinase activity (NK), biogenic amine content and sensory properties of natto are of great significance to consumers, which are affected by strains and fermentation methods. In this study, changes in the pH, biogenic amine and free amino nitrogen (FAN) contents, NK and protease activities, and sensory characteristics of natto prepared using Bacillus subtilis GUTU09 combined with different strains (Lactobacillus, Bifidobacterium and Mucor) and fermentation methods were investigated. The combination of two strains showed the best fermentation performance among all samples. The NK and protease activity and FAN content in double-strain fermentation increased by 10.33 FU/g, 88.78 U/g, and 2.34 g/kg, respectively, compared with those in single-strain fermentation. Sensory evaluation demonstrated that mixed fermentation primarily affected the sensory acceptance. This method also reduced the contents of various biogenic amines in natto compared with single-strain fermentation. Tyramine, cadaverine, spermine, and spermidine were significantly reduced, whereas histamine was slightly increased. The total biogenic amines decreased from 390.76 mg/kg to a minimum of 16.16 mg/kg. Some Mucor strains also reduced the contents of various biogenic amines. In the dual-bacteria fermentation of Mucor and GUTU09, co-fermentation has advantages over stage-fermentation, with higher NK and protease activity and higher sensory scores. Correlation analysis showed that the formation and accumulation of some biogenic amines in natto prepared using different microbial combinations were related to NK activity and pH. All these results showed that the quality of natto was improved by mixed fermentation and suitable fermentation methods, which laid a foundation for its potential industrial application.

Effects of different strains and fermentation method on nattokinase activity, biogenic amines, and sensory characteristics of natto

Predominant processing adaptability of Staphylococcus xylosus strains isolated from Chinese traditional low-salt fermented whole fish.

We previously screened a whole-cell lipase EC 3.1.1.3 from the novel strain Aspergillus niger GZUF36, which exhibited 1,3-selectivity in the synthesis of 1,3-diacylglycerol via glycerolysis. However, the mechanism of lipase selectively in catalyzing the sn-1,3 position remains ambiguous. This work was performed to investigate the 1,3-selective mechanism of lipase using glycerolysis to synthesize 1,3-diacylglycerol (1,3-DG) as a model reaction by changing solvent(s) and water activity (aw), and addition of salt hydrate pair. The measured diacylglycerol yield was also used to examine lipase activity. Results indicated that not only organic solvent and aw have strong effect on the sn-1,3 selectivity, but also ions of salt hydrate pair also affected selectivity. Lipase conformation was altered by hydrophobic interactions of the solvent, aw, or ions of salt hydrate, resulting in distinct sn-1,3 selectivity of the lipase. The salt hydrate pair changed the lipase conformation and selectivity not only by aw but also by static interactions, which was rarely reported. These parameters also affected lipase activity. The lipase displayed the highest selectivity (about 88%) and activity in solvents of t-butanol and n-hexane (1:29, v/v) at aw 0.43. The results demonstrated that the sn-1,3 selectivity and activity of the lipase from A. niger GZUF36 may be improved by control of some crucial factors. This work laid a foundation for the application of lipase in the synthesis of 1,3-DG and other structural and functional lipids.

Effects of organic solvent, water activity, and salt hydrate pair on the sn-1,3 selectivity and activity of whole-cell lipase from Aspergillus niger GZUF36.

Laping He

Papers

Effects of replacing fat with Perilla seed on the characteristics of meatballs.

Exploring the bacterial community for starters in traditional high-salt fermented Chinese fish (Suanyu).

Effects of different strains and fermentation method on nattokinase activity, biogenic amines, and sensory characteristics of natto

Predominant processing adaptability of Staphylococcus xylosus strains isolated from Chinese traditional low-salt fermented whole fish.

Effects of organic solvent, water activity, and salt hydrate pair on the sn-1,3 selectivity and activity of whole-cell lipase from Aspergillus niger GZUF36.