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This study demonstrates that the co-inoculation with Lactiplantibacillus plantarum, Pichia fermentans and Staphylococcus saprophyticus accelerates catfish frame fish sauce fermentation. Over a 3-day period, significant changes occurred in physicochemical properties, microbial profiles, flavor compounds, and metabolomic spectra. Notable increases in acidity coupled with decreases in glucose underscored the robust environmental adaptability of the employed microorganisms. A reduction in total amino acids, alongside a rise in umami amino acids, suggested flavor enhancement. GC-MS analysis identified 40 key volatile compounds, with esters and aldehydes crucial for aroma development. UPLC-QTOF-MS-based untargeted analysis identified 934 metabolites, with 377 differential metabolites being vital (VIP > 1.5, P < 0.05), including amino acids, peptides, organic acids, nucleic acids, and fatty acids. Metabolites linked to amino acid metabolism, particularly phenylalanine and arginine, were associated with fermentation duration. These findings offer a theoretical basis for optimizing flavor and quality in fish sauces from fish by-products through accelerated fermentation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The correlation between microbiota succession and flavor development in Chinese traditional fermented fish (Suanyu) inoculated with mixed starter cultures was studied. The results showed that 17 free amino acids, 22 free fatty acids and 9 organic acids were present. A total of 81 aroma compounds were detected during Suanyu fermentation. Aldehydes were the most abundant aroma compounds in the early stage of fermentation and esters contributed most to the aroma in the later stage of fermentation. The correlation analysis of microbial succession and flavor dynamics based on bidirectional orthogonal partial least squares (O2PLS) suggested that in addition to starter cultures, other microorganisms including 2 bacteria genera and 11 fungi genera were also responsible for the formation of flavor compounds. These results may help focus further research to improve the flavor quality of traditional fermented fish., Competing Interests: Declaration of competing interest The authors attested that there were no conflicts of interest with respect to this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Fermentation is a traditional food preservation method and is widely used for improving food safety, shelf life, and organoleptic and nutritional attributes. Fermented fish are produced and consumed in different parts of the world and are an integral part of many food cultures. Furthermore, fermented fish are a source of interesting microbes and are an important industry in many countries. This review tries to update the types and manufacturing processes for fermented fish around the world. The emphasis is on this work related to fermented fish and their health benefits, as well as the contribution of microorganisms to their fermentation. A variety of different approaches have been used to determine and understand microbial composition and functionality. Moreover, some challenges and future research directions regarding fermented fish are also discussed in this review. Further research into fermented fish products is of crucial importance not only for the food industry but also for human health. However, extensive in vivo and toxicological studies are essential before the application of bioactive-rich fermented fish products for human health benefits.

This study investigated the effects of Lactobacillus plantarum 120, Saccharomyces cerevisiae 2018 and Staphylococcus xylosus 135 inoculation on N-nitrosodimethylamine (NDMA) and its precursors formation, and on microbiological characteristics of Chinese traditional fermented fish products (CTFPs). The results indicated that three strains could directly degrade NDMA in culture broth, and the highest degradation rate was observed in L. plantarum 120. The lactic acid bacteria counts in samples inoculated with L. plantarum 120 and mixed starter cultures were significantly (P < 0.05) higher than the others during the initial and middle fermentation stages (≤3 weeks). The final contents of total volatile base nitrogen, trimethylamine, dimethylamine, nitrite and NDMA in inoculated samples were significantly (P < 0.05) lower than those in spontaneous fermentation samples. According to these results, the inoculation with autochthonous starter cultures was a promising method to inhibit the NDMA and its precursors accumulation in CTFPs during fermentation process., (Copyright © 2018. Published by Elsevier Ltd.)

The main goal of this study was to investigate the dynamics, diversity and succession of microbial community present during the preparation of Suan yu (fermented fish), with and without starter cultures by high-throughput sequencing of 16S rRNA and ITS1 genes. Firmicutes and Ascomycota were the predominant phyla of bacteria and fungi, respectively, in all samples. At the genus level, Lactobacillus, Macrococcus and Staphylococcus were the predominating bacteria throughout the fermentation process, regardless of the inclusion of starter cultures. Saccharomyces was the predominating fungal genus in the early-fermentation stage of samples that inoculated starter cultures (MS), while the final product was dominated by Candida and Wickerhamomyces. Compared with naturally-fermented samples (NS; no starter cultures), Lactococcus, Leuconostoc, Enterococcus, Vibrio, Fusicolla and Torulaspora were inhibited and Aureobasidium emerged in samples inoculated with starter cultures (P < .05). Unweighted pair-group and principal component analyses of bacterial and fungal compositions revealed that microbiota structures differed between NS and MS samples. Redundancy analysis indicated that water content and pH might be important factors influencing the dominant bacterial and fungal community. Results indicated that microbial community were dynamic during fermentation process and the inoculation of mixed starter culture inhibited the growth of many organisms associated with food spoilage and contributed to the improvement of the quality of Suan yu products., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Phospholipid molecular species composition of Chinese traditional low-salt fermented fish (Suan yu) inoculated with different starter cultures was investigated. Fifty-six molecular species of phospholipid including 20 species of phosphatidylcholine (PC), 15 species of phosphatidylethanolamine (PE), 6 species of phosphatidylserine (PS), 9 species of lysophosphatidylcholine (LPC), and 6 species of lysophosphatidylethanolamine (LPE) were identified using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). PC (C16:0-C18:1), PE (C16:0-C22:6), PS (C15:0-C22:6), LPC (C22:6) and LPE (C22:5) were the predominant species. Bioactive polyene phospholipids mainly existed in PE. Furthermore, starter cultures exhibited different influence on phospholipid molecular species. Compared to naturally fermented Suan yu, more molecular species of PE and PS as well as polyene phospholipids were detected in the samples inoculated with Saccharomyces cerevisiae 31 and mixed starter cultures., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

To investigate the contribution of autochthonous microflora on free fatty acids (FFA) release and flavor development in low-salt fermented fish, three groups of processed fish, including bacteriostatic-acidification group (BAG), bacteriostatic group (BG), and spontaneous fermented fish (CG) were established. Results showed that addition of NaN 3 reduced microbial load in BAG and BG below 3.5 log CFU/g after 3 weeks of incubation. Activities of lipases and lipoxygenase declined markedly with increasing time, where BG had the highest activities, followed by CG and BAG. There is a 36.3% higher in the total FFA content in CG than that in BAG, indicating both microbial and endogenous lipases contributed to the FFA liberation in fermented fish while endogenous lipases play a major role. However, compared to BAG and BG, largely higher levels of volatile compounds were observed in CG, suggesting that autochthonous microflora dominated the generation of volatile flavor compounds in fermented fish., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Summary: The microbial dynamics, diversity and succession characterisation during the fermentation of fish‐chili paste, with and without starter cultures by high‐throughput sequencing, were investigated to identify the relationship between microbial composition and the accumulation of biogenic amines. Results showed that Firmicutes was the predominant phylum, and Lactobacillus and Weissella were the main genera during fermentation process, regardless of the inclusion of starter cultures. Compared with naturally fermented samples (NS; no starter cultures), Pediococcus and Staphylococcus flourished in samples inoculated with SBM‐52 starter culture (Staphylococcus xylosus + Staphylococcus carnosus + Pediococcus pentosaceus + Pediococcus acidilactici). Staphylococcus also accounted for a larger proportion in samples inoculated with WBX‐43 starter culture (Staphylococcus xylosus + Staphylococcus carnosus). Furthermore, Enterobacter was inhibited in inoculated samples. Unweighted pair‐group method with arithmetic means and principal component analyses revealed that microbiota structures were different among NS, SBM and WBX samples. In case of biogenic amines, the concentration of putrescine, cadaverine and tyramine increased to higher levels in NS samples compared with inoculated samples. Our work also investigated the relationship between core bacterial communities and biogenic amines. This study provided an improved understanding for the effects of starter cultures on the microbial community and the quality of fish‐chili paste. [ABSTRACT FROM AUTHOR]

Fermentation is an important way to process and preserve fish. It not only gives the product a unique flavor and texture, but it also contributes to increased nutritional value and better functional properties. The production of fermented fish relies on naturally occurring enzymes (in the muscle or the intestinal tract) as well as microbial metabolic activity. This review focuses on the role of microorganisms on texture change, flavor formation, and biogenic amines accumulation in fermented fish. In addition, the production conditions and the major biochemical changes in fermented fish products are also introduced to help understand the factors influencing the quality of fermented fish. Moreover, prospects for further research of fermented fish are discussed. [ABSTRACT FROM AUTHOR]

Summary: To evaluate the effects of irradiation and thermal treatments on the quality characteristics of the vacuum‐packaged low‐salted fermented fish (Suanyu) during 90‐day storage, thermal‐treated group (TTG), irradiated‐treated group (ITG) and non‐treated group (CG) were prepared. The results showed that total viable counts reduced by 4.49 and 4.67 log CFU/g after thermal and irradiation treatments, respectively, and no coliforms and pseudomonas growth occurred during storage. Compared with CG, lower levels in L*, springiness, chewiness of TTG and higher levels in L*, b* and chewiness of ITG were detected after 90‐day storage. Total biogenic amines content was significantly reduced in ITG compared with CG and TTG (P < 0.05). Both irradiation and thermal treatments have the potential to maintain quality of Suanyu during room storage. Compared with irradiation, thermal treatment could better stabilise the free amino acids and volatile compounds of Suanyu during room storage, but had some negative effects on texture quality. [ABSTRACT FROM AUTHOR]

Summary: The increased fish consumption correlates with increased hypersensitive reactions, which can reduce consumer's living quality. Therefore, the reduction by fish allergens by new technologies is important. The aim of this study was to evaluate the effect of different starter cultures, fermentation process and additives used in fermentation on immunological properties of fish allergens. The results showed that fermentation with Lactobacillus plantarum reduced the IgG‐ and IgE‐binding capacity (39.71 ± 6.18% and 76.12 ± 4.73%, respectively) the most, compared with Staphylococcus xylosus and Saccharomyces cerevisiae, and the reduction rate was the highest atthe end of fermentation and an incubation concentration at 1.5% (v/w). A change in the NaCl content affected immunological properties of fish allergenic proteins during fermentation, while a change in glucose had less impact. In conclusion, fermentation can be used to reduce the immunological propertis of fish allergens due to structural changes in proteins caused by enzymatic hydrolysis, acidity or ion strength. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the effects of long-term storage at various temperatures (4, 25, and 358C) on flavor and microbiological and physicochemical qualities of traditional Chinese low-salt fermented fish (Suanyu). Food spoilage and pathogenic bacteria (coliforms, Pseudomonas, and Salmonella) were inhibited during the 90 days of storage at all temperatures. Lactic acid bacteria, yeast, and total viable bacteria counts of samples stored at 358C were reduced sharply, whereas other parameters were stable. Compared with refrigerated storage (48C), higher storage temperatures (25 and 358C) accelerated moisture migration, lipid oxidation, and proteolytic degradation. Storage time had a greater effect than storage temperature on the increase of volatile compounds in Suanyu. Refrigerated storage was better than higher storage temperatures (25 and 358C) for maintaining the odor quality of Suanyu during the storage period. Total biogenic amine concentrations in all samples were -200 mg/kg. Suanyu can be consumed safely during 90 days of storage based on the levels of spoilage and pathogenic bacteria and concentrations of biogenic amines, but refrigerated storage effectively slows down the microbial and physicochemical changes, resulting in better organoleptic quality. The results of this study will be useful for processors controlling the safety and quality of fermented fish during transport and storage. [ABSTRACT FROM AUTHOR]

Effects of wine and dairy yeast fermentation on chemical constituents of tilapia fish head hydrolysate supplemented with glucose in an unsalted and acidic environment were investigated. Three wine yeasts (Torulaspora delbrueckii Biodiva, Saccharomyces cerevisiae Lalvin EC-1118 and Pichia kluyveri Frootzen) and one dairy yeast (Kluyveromyces marxianus NCYC1425) were employed as single starter cultures, respectively, and were compared with one soy sauce yeast (Candida versatilis NCYC1433). Each yeast showed different growth kinetics and fermentation performance. Compared with C. versatilis NCYC1433, other yeasts presented a significant higher rate of glucose consumption (P < 0.05). Besides, K. marxianus NCYC1425 and P. kluyveri Frootzen produced more citric acid and succinic acid, respectively, while S. cerevisiae Lalvin EC-1118 exhibited higher pyruvic acid production. Significant lower levels of total free amino acids were observed in samples inoculated with wine yeasts relative to other yeasts (P < 0.05). Non-soy sauce yeasts produced increased various levels of esters and alcohols without traditional fish sauce unpleasant odorants, especially K. marxianus NCYC1425 and P. kluyveri Frootzen. The results confirmed that non-soy sauce yeasts are suitable for fish sauce flavor compound modification and to develop a fast fermentation process for saltless fish sauce from fish head, which could increase the acceptability of fish sauce and improve the utilization of fish by-products. [ABSTRACT FROM AUTHOR]

Summary: Sturgeon (Acipenser sinensis) meat has not been fully utilised due to quality defects which were raised by Chinese sturgeon processing industry. This study was aimed to develop a high‐quality sturgeon meat product and the effect of fermentation on qualities was studied. Results showed that fermentation with Saccharomyces cerevisiae could enhance 'mushroom', 'fruity' and 'chocolate' flavour by 1‐octen‐3‐ol, ethyl acetate and 3‐methyl‐butanal; and enrich flavour through mild lipid oxidation and hydrolysis. In addition, fermentation could give an attractive colour with higher a*, b* and L* value. Texture properties were also improved with higher hardness, springiness, gumminess and chewiness. Higher free amino acids, TCA‐soluble peptides and taste score in fermented sturgeon meat indicated better flavour and taste. The organoleptic evaluation suggested an overall satisfactory of wine‐aroma sturgeon meat by fermentation with S. cerevisiae. [ABSTRACT FROM AUTHOR]

Summary: To accelerate fermentation and improve quality of fermented fish, the impact of fermentation at elevated temperature on physicochemical, microbiological and flavour characteristics, as well as biogenic amines (BAs) accumulation of low‐salt fermented fish was investigated. Results showed that increasing temperature at later stage significantly promoted the growth of lactic acid bacteria, retarded the reduction of yeast and increased the titratable acidity, while staphylococci and enterobacteriaceae were inhibited to higher extent when fermented at elevated temperature. BAs contents in samples fermented at 30 °C during later stage were lower than those in the group fermented at 25 °C for 28 days, and the lowest values were observed in the sample initially fermented at 25 °C for 10 days followed by fermentation at 30 °C for 18 days. Furthermore, fermentation at elevated temperature at later stage favoured the formation of desired volatile flavour compounds. Results suggested that fermentation at elevated temperature at later stage could reduce BAs accumulation and enhance quality attributes of low‐salt fermented fish. The impact of fermentation temperature on quality attributes of low‐salt fermented fish. [ABSTRACT FROM AUTHOR]

Summary: In this study, three previously isolated dominant autochthonous strains from Chinese traditional fermented fish products (CTFPs), namely Lactobacillus plantarum 120, Saccharomyces cerevisiae 2018 and Staphylococcus xylosus 135, were used to evaluate their nitrite degradation abilities. The highest nitrite degradation rate (NDR) was observed in L. plantarum 120 (90.70%), followed by S. cerevisiae 2018 (78.75%) and S. xylosus 135 (13.09%). The nitrite reductase activities of L. plantarum 120 and S. cerevisiae 2018 could be promoted by appropriate sodium chloride contents (4%–6%). Meanwhile, nitrite could be degraded in soluble grass carp proteins, and the NDR was positively associated with the protein concentration. Inoculation with L. plantarum 120, S. cerevisiae 2018 and S. xylosus 135 significantly (P < 0.05) decreased the nitrite and nitrate concentrations in CTFPs. Therefore, dominant autochthonous strains, especially L. plantarum 120 and S. cerevisiae 2018, could be used as promising starter cultures to inhibit nitrite accumulation in CTFPs. The nitrite degradation pathways of dominant autochthonous strains isolated from Chinese traditional fermented fish. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of mixed kojis on essential indices of fish sauce. Fish sauce inoculated with mixed kojis ( FSB, Aspergillus oryzae koji: Aspergillus niger koji = 3:1) and A. oryzae koji ( FSA, control) was prepared. At the end of fermentation, the content of amino nitrogen, total soluble nitrogen, Free amino acid (FAA) and glutamic acid in FSB increased by 7.50%, 7.84%, 9.80% and 28.43% compared to FSA, due to higher acid protease activity in mixed kojis. Moreover, flavour groups including phenols, ketones and nitrogen-containing compounds in FSB were also improved. According to the results of sensory evaluation, FSB showed higher intensity of umami and caramel attributes, lower intensity of ammonia and sour attributes. All the results suggested that the usage of mixed kojis to produce fish sauce was an effective method that can accelerate the fermentation process and improve the flavour of fish sauce made with freshwater fish by-products. [ABSTRACT FROM AUTHOR]

Effect of endogenous proteolysis on myofibrillar conformational changes under acidic condition was investigated by spectroscopic techniques. The result of intrinsic tryptophan fluorescence showed that tryptophan residues were exposed to polar environment by acid denaturation of protein and participation of endogenous proteolysis. Extrinsic fluorescence indicated that average surface hydrophobicity (ShANS) decreased by reduction of pH but increased by endogenous proteolysis. Second-derivative UV-spectroscopy implied that the decrease of ShANS under acidic condition may be due to burying of some aromatic amino acid residues into hydrophobic cores induced by acid-induced aggregation, such as tyrosine, while ShANS increased by exposure of some hydrophobic amino acids due to the effect of endogenous proteases. Raman spectra verified the changes in microenvironment of tryptophan and tyrosine residues, and showed that aliphatic amino acids were mainly exposed to polar solvent by both acid denaturation and endogenous proteolysis. In addition, new disulphide bonds were less likely to form by acid-induced aggregation and proteolytic cleavage, while random coils increased and smaller water domains were found. [ABSTRACT FROM AUTHOR]

Effect of autochthonous starter cultures on the volatile flavour compounds of Chinese traditional fermented fish was studied. Lactobacillus plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31, isolated from Suan yu, were selected as starter cultures. Volatiles were extracted by headspace solid-phase microextraction ( SPME) and analysed by gas chromatography-mass spectrometry technology ( GC- MS). Esters and alcohols were the main components of volatiles, accounting for over 50 percentage points in all samples. The highest content of esters (3034.54 μg kg−1) was observed in S1 inoculated with L. plantarum 120, while the highest content of alcohols (2164.53 μg kg−1) and ketones (379.98 μg kg−1) was detected in S3 inoculated with S. cerevisiae 31. The content of acids and aldehydes was lower in inoculated samples. Principal component analysis revealed that the volatile composition was primarily influenced by the nature of the starter cultures. L. plantarum 120 and S. xylosus 135 could accelerate fermentation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the lipolysis and lipid oxidation of Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31 in Suan yu. Suan yu were made inoculated with and without two strains at different stages, and model systems of emulsions were also established. Lipolysis and lipid oxidation were evaluated by determining the changes in free fatty acid ( FFA) content and composition, conjugated diene ( CD) value and thiobarbituric acid reactive substances ( TBARS) value. The total FFA of the sample without cultures increased from 476.61 mg/100 g fat to 1413.89 mg/100 g fat after 5 weeks fermentation, while those of samples with cultures declined to 258.98 and 452.89 mg/100 g fat, respectively. On the other hand , CD and TBARS values of samples with inoculation markedly increased. In the model system, higher FFA, CD and TBARS values for the samples added with CFE were observed. This study showed that Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31 made a significant contribution to lipolysis and lipid oxidation during the processing of Suan yu. [ABSTRACT FROM AUTHOR]

In this study,Lactobacillus plantarum 120, Lactobacillus plantarum 145,andPediococcus pentosaceus 220, which exhibit optimal properties among those isolated from the traditional fermented fish products, were selected as the starter cultures for the preparation of fermented whole carp. During the fermentation, samples inoculated with different single starter cultures showed rapid growth of lactic acid bacteria (LAB), decline in pH, suppression in the growth of main microflora, as well as increase of thiobarbituric acid reactive substances (TBARS) values and total volatile base nitrogen (TVB-N). Quantities of nonprotein nitrogen (NPN) and free amino acids (FAA) were higher in whole carp with starter cultures compared to those in the control. Severe hydrolysis of protein was observed utilizing sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis during fermentation. Moreover, sensory evaluation indicated the higher acceptability of fermented products. The results show that inoculation with the autochthonous starter cultures reduced fermentation time and improved the quality of samples. Therefore, isolates of the strains could be used as potential starters for the fermentation of whole carp. [ABSTRACT FROM AUTHOR]

Abstract: In this study, three groups of mixed starter cultures (S1: Lactobacillus plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31; S2: L. plantarum 145, S. xylosus 135 and S. cerevisiae 22; S3: Pediococcus pentosaceus 220; S. xylosus 135 and S. cerevisiae 22), isolated from Suan yu, were inoculated to produce the traditional fermented fish. After 42 days fermentation at 24 °C, Suan yu inoculated with different mixed starter cultures underwent rapid growth of lactic acid bacteria (LAB), declined pH, suppressed increase of thiobarbituric acid (TBARS) and total volatile base nitrogen (TVB-N) as well as growth of spoilage bacteria and pathogens. Besides, Suan yu had higher contents of non-protein nitrogen (NPN) and total free amino acids (FAA) compared to the control (P < 0.05). The muscle proteins were severely hydrolyzed during fermentation (SDS-PAGE). Moreover, the sensory evaluation indicates the fermented fish was more widely accepted than the control. The results suggest that the inoculation with S1, S2 and S3 reduced the lag time that fermentation began and improved the quality of Suan yu. [Copyright &y& Elsevier]

In this study, two groups of mixed starter cultures ( S1, S2), which were isolated from Suan yu, were inoculated for this experimental product, and a batch without starters was used as the control. The effect of the mixed starter cultures on the suppression of biogenic amine ( BA) produced during the ripening of Suan yu was investigated. Changes in BA, p H, total volatile base nitrogen ( TVB-N), microbial counts and free amino acids ( FAA) contents were detected during ripening. The results show that the mixed starter cultures rapidly decreased p H, inhibited the growth of contaminant microorganisms emerged in the sample and drastically reduced the accumulations of tyramine, putrescine and cadaverine. However, histamine and spermine were not produced in any batch. Besides, p H, FAA and BA production were not directly correlated. The study suggests that inoculation with S1 and S2 inhibited BA, thereby improving the product safety. [ABSTRACT FROM AUTHOR]

Abstract: Changes in protein composition and physicochemical properties of silver carp sausages during fermentation were investigated. As fermentation progressed, the amount of salt-soluble and water-soluble proteins decreased gradually with a concomitant increase in insoluble proteins and non-protein constituents. The rapid reduction in pH to 4.5 within 48h of fermentation coincided with a progressive increase in titratable acidity. The increasing content of TCA-soluble peptides during fermentation indicated intensive degradation of muscle proteins. SDS–PAGE showed that muscle proteins tended to aggregate into large polymers through disulphide bonds and non-disulphide covalent bonds during fermentation, which may be responsible for the formation of superior textural properties of silver carp sausages. [Copyright &y& Elsevier]

Abstract: The types of interactions and the proteins involved in the formation of gel network of fermented silver carp mince were investigated. Results showed that the amount of each type of protein interactions varied significantly depending on fermentation time. The content of sulphydryl groups decreased continually with a concomitant increase in disulphide bonds during fermentation. The higher gel strength and more compact fibrous network of fermented silver carp mince corresponded to a higher percentage of hydrophobic interactions, disulphide bonds and non-disulphide covalent bonds. SDS–PAGE showed that the major myofibrillar proteins, particularly myosin heavy chain were involved in the formation of aggregates through hydrophobic interactions and disulphide bonds during fermentation. Furthermore, low molecular weight proteins probably produced by proteolysis were also involved in the formation of gel matrix. [Copyright &y& Elsevier]

Abstract: The effect of fermentation with Pediococcus pentosaceus at different temperatures ranging from 15 to 37°C on the quality characteristics of silver carp sausages was investigated. Higher temperature stimulated the rapid growth of lactic acid bacteria, resulting in a rapid decline in pH, and consequently suppressed the growth of Pseudomonas, Micrococcaceae and Enterobacteriaceae. However, increasing fermentation temperature gave a progressive increase in total volatile basic nitrogen and biogenic amines in fermented silver carp sausages. Histamine was the main biogenic amine, exceeding 100mg/kg after 48h of fermentation at temperatures above 30°C. Higher content of non-protein nitrogen and α-amino nitrogen correlated with the electrophoretic studies, which showed that proteolysis of high molecular weight myofibrillar and sarcoplasmic proteins was more prominent at higher fermentation temperatures. Products fermented at 23–30°C showed greatest consumer preference and most favourable textural properties. [Copyright &y& Elsevier]

How to ensure low-salt fermented food safety with good flavor under non-acidic conditions is a challenge. Temperature is one of the key environmental parameters that affect the growth of microorganism and enzyme activity. The effects of fermentation for 4 days at 4 °C, 10 °C, 20 °C and 20-10 °C (20 °C for 2 days followed by 10 °C for 2 days) on the flavor, microbial and physicochemical properties of low-salt fermented bream were investigated. Results showed that compared with 4 °C-fermentation, higher fermentation temperature (10 °C, 20 °C, 20-10 °C) could accelerate protein degradation and facilitate the formation of flavor substances during fermentation of bream. The volatile flavor compounds of 20 °C and 20-10 °C two-stage fermentation groups were similar. After 4 days of fermentation, highest content of alcohols, ketones and esters were observed in two-stage fermentation group (20-10 °C). For comparison with 20 °C-fermentation, two-stage fermentation (20-10 °C) reduced the contents of total volatile basic nitrogen, cadaverine, putrescine and total biogenic amines significantly (p < 0.05), and inhibited the growth of harmful microorganisms (Pseudomonas and Coliforms). Results suggested that two-stage fermentation with different temperature provided a potential method that facilitated improving the flavor and safety of low-salt fermented bream. • Higher temperature caused rapid growth of microorganisms and accumulation of biogenic amines. • Two-stage fermentation (20-10 °C) inhibited the formation of biogenic amines. • Two-stage fermentation (20-10 °C) benefited against undesirable microorganisms. • Improved flavor could be obtained using two-stage fermentation with different temperature. [ABSTRACT FROM AUTHOR]

Abstract To better understand the role of fermentative microorganisms in lipid changes during the processing of fermented fish, sterile fish paste with or without the antioxidant tert-butylhydroquinone (TBHQ) was used to investigate the roles of three strains isolated from traditional fermented fish in free fatty acid (FFA) liberation and lipid oxidation. The results showed that the addition of 0.03% TBHQ had no significant influence (P > 0.05) on the strain growth but could effectively inhibit fatty acid oxidation. Staphylococcus xylosus 135 demonstrated the highest liberation of FFAs, followed by Saccharomyces cerevisiae 31, with its released FFAs being almost all polyunsaturated fatty acids (PUFA). Furthermore, the highest amount of PUFA oxidation in FFAs was observed in the samples inoculated with Staphylococcus xylosus 135 (802 mg/kg DM), followed by Lactobacillus plantarum 120 (476 mg/kg DM) and Saccharomyces cerevisiae 31(388 mg/kg DM). The results suggested that Staphylococcus xylosus may play a major role in the lipolysis and lipid oxidation during the processing of fermented fish. Lactobacillus plantarum also contributed to the fatty acid oxidation although it had no obvious lipolysis ability. Highlights • Role of microbes in free fatty acids release and oxidation was determined. • 0.03% TBHQ had no effect on strain growth but inhibit fatty acids oxidation. • Oxidation caused the major loss of fatty acids during fermentation of fish. • Staphylococcus xylosus 135 had the highest ability of lipolysis and lipid oxidation. • Lactobacillus plantarum 120 contributed to lipid oxidation but had no lipolytic activity. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate endogenous proteolytic activities in a cod product and their impact on muscle proteins and textural properties during fermentation and storage. The result of specific proteolytic activities showed that cathepsins, especially cathepsin B, had the highest activities during fermentation and storage. SDS–PAGE indicated more degradation of myofibrillar proteins by cathepsin L than other proteases and that the hydrolysis by cathepsins was pronounced in the last stage of fermentation. Texture analysis showed that cathepsins had a negative impact on gel strength and this impact increased in the last stage of fermentation. However the product still had a firm texture. During storage (4 °C) for one week, no significant changes were seen in the gel strength. In conclusion, cathepsins had more impact on muscle proteins and textural properties than other proteases during fermentation but had little impact on gel strength during storage at 4 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • The inoculation of mixed starter cultures and addition of spices mixture could effectively inhibit BAs production. • The inoculation of starter cultures could inhibit Enteroccoccus and other microorganisms. • Spices introduced Bacillus into Suanyu. • Staphylococcus , Macrococcus , and Lactobacillus were the core microbial genus in Suanyu. • Fermentation with starter cultures and spices could improve the safety of fermented fish. Suanyu is one of the traditional Chinese fermented fish products with a pleasant flavor. The present study sought to evaluate the effects of starter cultures and spices on the physicochemical properties and microbial flora of Suanyu after fermentation and storage. The results indicated that fermentation with mixed starter cultures could lower the pH and inhibit TVB-N formation in Suanyu after fermentation and during storage. Moreover, inoculation of starter cultures could promote free amino acids production during storage. Additionally, inoculation of mixed starter cultures and spices mixture could effectively inhibit the formation of most biogenic amines in Suanyu, revealing the significant role of mixed starter cultures. Staphylococcus , Macrococcus , and Lactobacillus were the core microbial genus in Suanyu. The inoculation of starter cultures could inhibit Enteroccoccus and other microorganisms, while spices introduced Bacillus into Suanyu. The study results provide a theoretical basis for the industrial production and storage of Suanyu. [ABSTRACT FROM AUTHOR]

The effects of commercial starter cultures on the quality characteristics of fermented fish-chili paste were investigated. Five batches of fish-chili paste were prepared with different starter cultures, namely, SBM-52 (Staphylococcus xylosus, Staphylococcus carnosus, Pediococcus pentosaceus and Pediococcus lactis), PRO-MIX5 (Staphylococcus xylosus, Lactobacillus plantarum and Lactobacillus sakei), WBX-43 (Staphylococcus xylosus and Staphylococcus carnosus) , V3 (Lactobacillus plantarum), and CO (spontaneous fermentation) as the control. The results showed that all the starter cultures accelerated the growth of lactic acid bacteria and obviously reduced the Enterobacteriaceae count compared with the CO batch. SBM-52, PRO-MIX5 and V3 quickly reduced the pH, and there was no obvious difference in the protease activities among these five batches (P > 0.05). The SBM-52 batch displayed a significantly higher level of total free amino acids than the control (P < 0.05). The accumulation of organic acids was mainly due to lactic acid in all the samples. Volatile analysis indicated that more ester compounds were detected in WBX-43 compared with the other samples. E-nose analysis showed an obvious difference in the overall odor among the different samples. In conclusion, the starter cultures of WBX-43 and SBM-52 could be used for the production of high-quality fish-chili paste with better flavor. • Effects of commercial starter cultures on the fish-chili paste were investigated. • Starter cultures benefit microbial quality against the undesirable microorganisms. • An appropriate addition of starter cultures produces more pleasant flavor. [ABSTRACT FROM AUTHOR]