Biochemical, Nutritional, and Sensory Quality of the Low Salt Fermented Shrimp Paste

Evaluation of the biogenic amines in low-salt shrimp paste cooked under various conditions

Shrimp paste, a type of traditional Chinese food prepared from shrimp fermented with salt, contains biogenic amines (BAs). In this study, the BA content, salinity, and pH of eight commercial low-salt shrimp pastes were analyzed. In addition, the influences of various cooking conditions on the BA content of it were evaluated by HPLC. The total BA amount per product ranged between 32.39 and 1051.16 mg/kg. The salinity and pH were found significantly inversely correlated with the total BA amount. Of the cooking methods tested, after microwave heating and stir-frying, the total BA amount of shrimp paste, which showed the highest BA amount among 8 samples, declined from 1051.16 to 598.48 and 650.49 mg/kg, respectively; however, boiling or steaming showed no significant effects on the total BA amount. These results indicated possible health risk of low-salt shrimp paste whereas the risk could be reduced by choosing appropriate cooking method.

Selection of a Fermentation Strategy for the Preparation of Clam Sauce with Acceptable Flavor Perception

Flavor, which mainly depends on volatile compounds, is an important index for evaluating the quality of clam sauce. This study investigated the volatile compounds in clam sauce prepared using four different methods and the influence of aroma characteristics. Fermenting a mixture of soybean koji and clam meat improved the flavor of the final product. Solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) identified 64 volatile compounds. Nine key flavor compounds, namely, 3-methylthio-1-propanol, 2-methoxy-4-vinylphenol, phenylethyl alcohol, 1-octen-3-ol, α-methylene phenylacetaldehyde, phenyl-oxirane, 3-phenylfuran, phenylacetaldehyde, and 3-octenone, were selected using variable importance in projection (VIP). The results of the electronic nose and tongue detection of the aroma characteristics of the samples prepared by four different fermentation methods were consistent with those of GC-MS analysis. The clam sauce prepared by mixing soybean koji with fresh clam meat possessed better flavor and quality than that prepared via other methods.

Bacillus subtilis K-C3 as Potential Starter to Improve Nutritional Components and Quality of Shrimp Paste and Corresponding Changes during Storage at Two Alternative Temperatures

This study aimed to evaluate Bacillus subtilis K-C3 as a potential starter to improve shrimp paste quality, particularly in terms of nutritional profiles. The quality/characteristic changes of shrimp paste with and without inoculation during storage for 18 months when stored at low (4 °C) and room (28 °C) temperature were also investigated. The results found that this B. strain increased essential amino acids (EAAs) and polyunsaturated fatty acids (PUFAs), as well as antioxidant properties including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, ferric reducing antioxidant power (FRAP) and metal chelating activity in the experimental shrimp paste compared to traditional shrimp paste (p < 0.05). The faster development of some characteristics of inoculated samples were also noted, as indicated by the higher total viable count (TVC), formal and amino nitrogen content, pH, and browning index, as well as biogenic amines, indicating different quality which may be further responsible for different product acceptability. The changes in quality/characteristics of shrimp paste were observed throughout the 18 months of storage. Shrimp paste stored at room temperature accelerated those changes faster than samples stored at low temperature (p < 0.05); however, the quality of them still meets the product’s standard even storage for 18 months. Meanwhile, shrimp paste stored at a low temperature had an amount of yeast and mold over the limitation (>3.00 log CFU/g), indicating food spoilage. Thus, storage at room temperature can extend this product’s shelf-life better than storage at low temperature. Overall, inoculation with B. subtilis K-C3, in conjunction with storage at room temperature, resulted in quality improvement and maintenance in shrimp paste, particularly in the aspects of nutritional profiles and safety concern, as the shrimp paste should have a shelf-life of at least 18 months.

The Influence of Lactic Acid Bacteria Fermentation on the Bioactivity of Crayfish (Faxonius limosus) Meat

In recent years, new raw materials have been sought for use in processing. This category certainly includes invasive crayfish Faxonius limosus. One of the problems associated with their use is their short microbiological shelf life. Therefore, in the research presented here, an attempt was made to ferment crayfish meat with strains of Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, Lactobacillus casei, and yogurt culture. The analyses included an evaluation of changes in the microbial quality of the material, the content of free amino acids, reducing sugars, ascorbic acid, and the antioxidant properties of the fermented meat. Changes in the canthaxanthin content and the number of sulfhydryl groups and disulfide bridges were also evaluated. The study showed that carrying out lactic fermentation resulted in a decrease in meat pH (8.00 to 7.35–6.94, depending on the starter culture). Moreover, the meat was characterized by an increase in FRAP (2.99 to 3.60–4.06 mg AAE/g), ABTS (2.15 to 2.85–3.50 μmol Trolox/g), and reducing power (5.53 to 6.28–14.25 μmol Trolox/g). In addition, the study showed a favorable effect of fermentation on the content of sulfhydryl groups in the meat as well as for ascorbic acid content. The results obtained can serve as a starting point for the further development of fermented products based on crayfish meat.

Fermented shellfish condiments: A comprehensive review

Fermented shellfish condiments are globally consumed especially among Asian countries. Condiments, commonly used as flavor enhancers, have unique sensory characteristics and are associated with umami and meaty aroma. The main reactions that occur during fermentation of shellfish include proteolysis by endogenous enzymes and microbial activities to produce peptides and amino acids. The actions of proteolytic enzymes and microorganisms (predominantly bacteria) are found to be largely responsible for the formation of taste and aroma compounds. This review elaborates different aspects of shellfish fermentation including classification, process, substrates, microbiota, changes in both physicochemical and biochemical components, alterations in nutritional composition, flavor characteristics and sensory profiles, and biological activities and their undesirable impacts on health. The characteristics of traditional shellfish production such as long duration and high salt concentration not only limit nutritional value but also inhibit the formation of toxic biogenic amines. In addition, this review article also covers novel bioprocesses such as low salt fermentation and use of novel starter cultures and/or novel enzymes to accelerate fermentation and produce shellfish condiments that are of better quality and safer for consumption. Practical Application: The review paper summarized the comprehensive information on shellfish fermentation to provide alternative strategies to produce shellfish comdiments that are of better quality and safer for consumption.

Comparative Analysis of Flavor, Taste, and Volatile Organic Compounds in Opossum Shrimp Paste during Long-Term Natural Fermentation Using E-Nose, E-Tongue, and HS-SPME-GC-MS

The present study focused on the determination of color, flavor, taste, and volatile organic compounds (VOCs) changes of shrimp paste fermented for 1, 2, 3, and 8 years by E-nose, E-tongue, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). During fermentation, the color of shrimp paste turned dark brown with decreases in L*, a*, and b* values. Inorganic sulfide odor was dominant in all fermented samples. The umami, richness, and aftertaste-B reached a maximum in year 3 of fermentation. A total of 182 volatiles, including long-chain alkanes, esters, aldehydes, olefins, ketones, acids, furans, and pyrazines, were detected. Sixteen VOCs including dimethyl disulfide, methional, trimethyl-pyrazine, (E,E)-2,4-heptadienal, benzeneacetaldehyde were selected as flavor markers. Correlation analysis showed that 94 VOCs were related to saltiness while 40, 17, 21, 22, and 24 VOCs contributed to richness, umami, aftertase-B, sourness, and bitterness, respectively. These novel data may help in optimizing fermentation duration to achieve target flavor indicators in opossum shrimp paste production.

Dynamic Changes in the Bacterial Community and Metabolic Profile during Fermentation of Low-Salt Shrimp Paste (Terasi)

Low-salt shrimp paste, or terasi, is an Indonesian fermented food made from planktonic shrimp mixed with a low concentration of salt. Since high daily intake of sodium is deemed unhealthy, reduction of salt content in shrimp paste production is desired. Until now, there is no reported investigation on the bacterial population and metabolite composition of terasi during fermentation. In this study, the bacterial community of terasi was assessed using high-throughput sequencing of the 16S rRNA V3–V4 region. From this analysis, Tetragenococcus, Aloicoccus, Alkalibacillus, Atopostipes, and Alkalibacterium were found to be the dominant bacterial genus in low-salt shrimp paste. GC/MS-based metabolite profiling was also conducted to monitor the metabolite changes during shrimp paste fermentation. Results showed that acetylated amino acids increased, while glutamine levels decreased, during the fermentation of low-salt shrimp paste. At the start of shrimp paste fermentation, Tetragenococcus predominated with histamine and cadaverine accumulation. At the end of fermentation, there was an increase in 4-hydroxyphenyl acetic acid and indole-3-acetic acid levels, as well as the predominance of Atopostipes. Moreover, we found that aspartic acid increased during fermentation. Based on our findings, we recommend that fermentation of low-salt shrimp paste be done for 7 to 21 days, in order to produce shrimp paste that has high nutritional content and reduced health risk.

Sodium Reduction in Traditional Fermented Foods: Challenges, Strategies, and Perspectives

Sodium salt is a pivotal ingredient in traditional fermented foods, but its excessive consumption adversely affects human health, product quality, and production efficiency. Therefore, reducing sodium salt content in traditional fermented foods and developing low-sodium fermented foods have attracted increasing attention. Given the essential role of sodium salt in the safety and quality of fermented foods, appropriate approaches should be applied in the production of low-sodium fermented foods. In this review, the challenges of sodium reduction in traditional fermented foods are presented, including the possible growth of pathogenic bacteria, the formation of hazardous chemicals, flavor deficiency, and texture deterioration. Physical, chemical, and biological strategies are also discussed. This review provides references for improving the quality and safety of low-sodium fermented foods.

Genome sequencing of cold-adapted Planococcus bacterium isolated from traditional shrimp paste and protease identification

BACKGROUND

Psychrophiles have evolved to adapt to freezing environments, and cold-adapted enzymes from these organisms can maintain high catalytic activity at low temperature. The use of cold-adapted enzymes has great potential for the revolution of food and molecular biology industries.

RESULTS

In this study, four different strains producing protease were isolated from traditional fermented shrimp paste, one of which, named Planococcus maritimus XJ11 by 16S rRNA nucleotide sequence analysis, exhibited the largest protein hydrolysis clear zone surrounding the colonies. Meanwhile, the strain P. maritimus XJ11 was selected for further investigation because of its great adaptation to low temperature, low salinity and alkaline environment. The enzyme activity assay of P. maritimus XJ11 indicated that the optimum conditions for catalytic activity were pH 10.0 and 40 °C. Moreover, the enzyme also showed an increasing activity with temperatures from 10 to 40 °C and retained more than 67% activity of the maximum over a broad range of salinity (50-150 g L^-1 ). Genome sequencing analysis revealed that strain XJ11 possessed one circular chromosome of 3 282 604 bp and one circular plasmid of 67 339 bp, with a total number of 3293 open reading frames (ORFs). Besides, 21 genes encoding protease, including three serine proteases, were identified through the NR database.

CONCLUSION

Cold-adapted bacterium P. maritimus XJ11 was capable of producing alkaline proteases with high catalytic efficiency at low or moderate temperatures. Furthermore, the favorable psychrophilic and enzymatic characters of strain P. maritimus XJ11 seem to have a promising potential for industrial application. © 2020 Society of Chemical Industry.

The Impact of Microbial Diversity on Biogenic Amines Formation in Grasshopper Sub Shrimp Paste During the Fermentation

Biogenic amines (BAs) and microbial diversity are important factors affecting food quality and safety in fermented foods. In this study, the bacterial and fungal diversity in grasshopper sub shrimp paste taken at different fermentation times were comprehensively analyzed, while the pH, colony counts, salinity, total volatile base nitrogen (TVB-N) and BA contents were quantitatively determined. In addition, the correlations among the samples with respect to microbial communities and the different parameters investigated especially BAs were also established. By combining the results of spearman correlation heatmap with the contents of BAs produced by the 102 halotolerant bacteria isolated from the grasshopper sub shrimp paste, six major genera of bacteria (Jeotgalibaca, Jeotgalicoccus, Lysinibacillus, Sporosarcina, Staphylococcus, and Psychrobacter) were found to be positively correlated with BA production level, suggesting that these bacteria might have a strong tendency to produce BAs. Other bacteria such as Lentibacillus, Pseudomonas, and Salinicoccus were considered as poor BA producers. The grasshopper sub shrimp paste was characterized by a relatively high abundance of Tetragenococcus, which was the dominant genus during the fermentation process, and it also produced a relatively high level of BAs but the spearman correlation heatmap revealed a negative correlation between T. muriaticus and BA level. Analysis of the species relevance network in grasshopper sub shrimp explained that the actual production of BAs by a certain strain was closely related to other species present in the complex fermentation system.