Novel insight into the formation and improvement mechanism of physical property in fermented tilapia sausage by cooperative fermentation of newly isolated lactic acid bacteria based on microbial contribution

Microbial interactions between Lactoplantibacillus plantarum and Rhodotorula mucilaginosa in the fermented fish juice system

Lactic acid bacteria and yeasts play important roles in fermented fish products. The present study investigated the interaction between Lactoplantibacillus plantarum and Rhodotorula mucilaginosa in a fermented fish juice system. The results demonstrated that the co-culture of L. plantarum L6 and R. mucilaginosa Y9 significantly increased the maximum specific growth and population of L. plantarum L6, and decreased the lag phase. During microbial interactions, R. mucilaginosa Y9 increased the concentration of soluble proteins and provided L. plantarum L6 with more TCA-soluble peptides. Additionally, these two strains showed co-metabolism of amino acids, such as glutamic acid and aspartic acid. Furthermore, the microbial interaction between two strains influenced the generation of volatile compounds. R. mucilaginosain Y9 removed some fishy-odors compounds, including 1-Octen-3-ol, 1-Hexanol and phthalate esters, but increased the accumulation of aldehyde compounds with unpleasant odors. In addition, co-cultivation promoted the generation of special compounds, such as γ-dodecalactone and 2-pentylfuran, which could improve the flavor quality of fermented fish products.

Improvement of the quality and safety of low-salt fish sauce by reconstruction of microbial community through cooperative fermentation of starters

Low-salt fermentation can speed up the fish sauce production, but it will lead to bad flavor and biogenic amine increase due to the metabolisms of spoilage microorganisms. In this work, cooperative fermentation of Tetragenococcus muriaticus, Bacillus subtilis, and Staphylococcus edaphicus that were isolated from traditional fish sauce were used to improve the quality and safety of low-salt fish sauce. The high-throughput sequencing found that these starters could significantly inhibited the spoilage microorganisms and reconstructed the microbial community with the total abundance over 99 % during fermentation. The amino acid nitrogen concentrations after cooperative fermentation were much higher than the natural fermentation, while the concentrations of biogenic amines were significantly inhibited. The headspace solid-phase microextraction gas chromatography-mass spectrometry identified 33 core volatile compounds (odor activity value ≥ 1), most of which with pleasant flavors were obviously improved by starters while those with unpleasant flavors were inhibited. The group-dimension correlation after genus influence calculation suggested that the starters contributed the most to the improvement of quality and safety due to their good fish sauce environment adaptability, spoilage microorganism inhibition, and protein and lipid metabolisms, with the influence ranking of T. muriaticus > S. edaphicus > B. subtilis. These strains are expected to be developed as special starters for the industrial production of low-salt fish sauce.

Three-Stage Solid-State Fermentation Technology for Distillers’ Grain Feed Protein Based on Different Microorganisms Considering Oxygen Requirements

The shortage of feed protein has plagued the development of the animal husbandry industry in China. In this study, a new three-stage fermentation technology for producing distillers’ grain feed protein was developed by introducing Aspergillus niger, yeast, and lactic acid bacteria. During the aerobic stage, there was a negative correlation between the reducing sugar content in the distillers’ grains and the amount of Aspergillus niger. The maximum reducing sugar concentration (36.89 mg g−1) was obtained when the oxygen supply was 30 mL min−1 and the fermentation time was two days. During the microaerophilic stage, the natural exchange of oxygen achieved optimal true protein enhancement (from 10.8% to 16.4%) among the three oxygen supply modes (natural exchange, forced ventilation, and filling supplement). During the anaerobic stage, lactic acid bacteria were inoculated for feed protein preservation and flavor enhancement. Our results provided insight and practical guidance for the high-value use of distillers’ grains.

Inhibition of Biogenic Amines in Fermented Tilapia Surimi by Collaborative Fermentation of Latilactobacillus sakei and Pediococcus acidilactici

Fermentation is an effective method for ameliorating the gelation properties of freshwater fish surimi, but the formation of biogenic amines (BAs) during fermentation should also be controlled. In this study, the BAs in fermented tilapia surimi were inhibited by the collaborative fermentation of Latilactobacillus sakei and Pediococcus acidilactici, followed by the revelation of the BA inhibition mechanism. Most of the BAs, and the total BA, as well as their precusor free amino acids (FAAs), were significantly reduced, while the umami FAAs, including glutamic acid and aspartic acid, were significantly enhanced after cooperative fermentation with starters. The high-throughput sequencing found that the spoilage microorganisms such as Acinetobacter, Micrococcus, and Streptococcus as well as Pediococcus were significantly inhibited, while Latilactobacillus rapidly became the dominant genus after cooperative fermentation, suggesting the better environment adaptability of L. sakei than P. acidilactici. The group-dimension correlation analysis suggested that Lactiplantibacillus had the greatest influence on the decrease in BAss. The quick acidification of starters, especially L. sakei, could inhibit the growth and metabolism of spoilage microorganisms to reduce BAs. L. sakei and P. acidilactici can be developed as the special starters to control the BA production in the fermented tilapia surimi through collaborative fermentation.

Fermented Fish Products: Balancing Tradition and Innovation for Improved Quality

The flavor profile of fermented fish products is influenced by the complex interplay of microbial and enzymatic actions on the raw materials. This review summarizes the various factors contributing to the unique taste and aroma of these traditional foods. Key ingredients include locally sourced fish species and a variety of spices and seasonings that enhance flavor while serving as cultural markers. Starter cultures also play a critical role in standardizing quality and accelerating fermentation. Flavor compounds in fermented fish are primarily derived from the metabolism of carbohydrates, lipids, and proteins, producing a diverse array of free amino acids, peptides, and volatile compounds such as aldehydes, ketones, alcohols, and esters. The fermentation process can be shortened by certain methods to reduce production time and costs, allowing for faster product turnover and increased profitability in the fermented fish market. Fermented fish products also show potent beneficial effects. This review highlights the importance of integrating traditional practices with modern scientific approaches. Future research directions to enhance the quality of fermented fish products are suggested.