Search Results (10)

Terasi is a traditional Indonesian fermented condiment made from rebon shrimp and salt. This study investigated the effects of Tetragenococcus halophilus inoculation and varying salt concentrations (6%, 12%, and 18%) on the physicochemical and sensory properties of terasi, compared to a non-inoculated control (25% salt), after 7, 14, and 21 days of fermentation. Inoculation decreased pH, soluble protein, and texture while increasing N-amino acid content, moisture, lactic acid bacteria (LAB), and color darkening. Higher salt levels raised pH, soluble protein, and texture but reduced N-amino acids, moisture, and LAB, resulting in a lighter color. LAB activity peaked on day 7, with moisture and texture increasing over time. Sensory analysis favored inoculated samples, and TOPSIS identified terasi with T. halophilus, 6% salt, and 7 days of fermentation as optimal in quality and preference. This formulation also demonstrated strong bioactivity, including antioxidant activity (3.90 mg AEAC/g sample by DPPH assay and 8.76 ± 0.22 mg AEAC/g sample by FRAP assay), antidiabetic potential via α-amylase and α-glucosidase inhibition (IC₅₀ of 1.95 and 7.24 mg/mL), and antimicrobial effects against E. coli (32.78 mm) and S. aureus (30.85 mm). These results suggest that T. halophilus-inoculated terasi offers enhanced quality and functional properties, supporting its potential as a health-promoting fermented food product. Full article

Chitinases are biotechnologically relevant enzymes that can be applied in such different sectors as pharmaceutical, food, environmental management, the biocontrol of pests and in the paper and cellulose industry. Microorganisms as filamentous fungi are the most important source of these biomolecules. The fungus Aspergillus niveus produces extracellular chitinase when cultured under submerged fermentation using shrimp shells, a residue generated by the fish industry, as a carbon source, for 96 h at 30 °C and 100 rpm. The particle size and concentration of the shrimp shells affected enzyme production. The chitinase was purified until electrophoretic homogeneity through the use of a Sephadex G-100 chromatographic column. It is a monomeric glycoprotein with a molecular mass of 47 kDa estimated using SDS-PAGE and 49.3 kDa determined using gel filtration. The carbohydrate content was 22.8%. The best temperature and pH for enzyme activity were 65 °C and 6.0, respectively. Approximately 80% of the enzymatic activity was preserved at pH 4.0 and 5.0 for 48 h, and the half-life (t₅₀) was maintained for 48 h at 40 °C. Salts, EDTA and β-mercaptoethanol did not affect chitinase activity significantly, but organic solvents reduced it. The kinetic parameters determined using p-NPGlycNac were K_m of 2.67 mmol L⁻¹, V_max of 12.58 U mg of protein⁻¹, Kcat of 2.47 s⁻¹ and K cat/K_m of 0.93 s⁻¹ mmol L⁻¹. The A. niveus chitinase inhibited the growth of all fungal strains used, especially Trichoderma harzianum (MIC = 22.4 μg mL⁻¹) and Penicillium purpurogenum (MIC = 11.2 μg mL⁻¹). The chitinase produced by A. niveus presented interesting characteristics that indicate its potential of application in different areas. Full article

Saeu-jeot is a widely consumed variety of jeotgal, a South Korean salt-fermented food. However, there is a lack of existing studies conducting nontargeted metabolomic analyses of saeu-jeot during fermentation. To evaluate the changes in saeu-jeot during fermentation, saeu-jeot samples were fermented for 360 days under controlled conditions. Samples collected at different time points were subjected to physicochemical (including nontargeted metabolomic analysis) and microbial analyses. As fermentation progressed, the pH decreased and acidity increased, whereas total nitrogen, amino-nitrogen, and specific amino acid concentrations increased. Nontargeted metabolite analysis supports these results. Metabolite profiling classified changes in saeu-jeot during fermentation into those occurring in the early (15–45 days), middle (60–180 days), and late (270–360 days) stages. Pathogenic bacteria were not detected, and biogenic amine levels were not elevated, suggesting that saeu-jeot is safe to consume. Overall, pH, amino-nitrogen, and pathogenic bacteria, according to the fermentation stage of saeu-jeot, can be useful parameters for evaluating the quality of salted shrimp. Full article

Fermented shrimp paste is a popular food in Asian countries. However, biogenic amines (BAs) are a typically associated hazard commonly found during the fermentation of shrimp paste and pose a food-safety danger. In this work, an autochthonic salt-tolerant Tetragenococcus muriaticus TS (T. muriaticus TS) strain was used as a starter culture for grasshopper sub shrimp paste fermentation. It was found that with the starter culture, putrescine, cadaverine, and histamine concentrations were significantly lower (p < 0.05) with a maximal reduction of 19.20%, 14.01%, and 28.62%, respectively. According to high-throughput sequencing data, T. muriaticus TS could change the interactions between species and reduce the abundance of bacterial genera positively associated with BAs, therefore inhibiting the BA accumulation during shrimp paste fermentation. Moreover, the volatile compounds during the fermentation process were also assessed by HS-SPME-GC-MS. With the starter added, the content of pyrazines increased, while the off-odor amines decreased. The odor of the shrimp paste was successfully improved. These results indicate that T. muriaticus TS can be used as an appropriate starter culture for improving the safety and quality of grasshopper sub shrimp paste. Full article

The increasing threat posed by antibiotic-resistant pathogens has prompted a shift to the use of naturally-derived antimicrobial peptides (AMPs) in place of chemical preservatives in controlling foodborne pathogens. In this study, ten peptides were identified from salt-fermented shrimps (Penaeus vannamei) using ultra-performance liquid chromatography-mass spectrometry. One of the peptides, designated PV-Q5 (QVRNFPRGSAASPSALASPR), with most features of an AMP, was further explored and found to possess strong antibacterial activity against Vibrio parahaemolyticus and Escherichia coli, with a minimum inhibitory concentration of 31.25 μg/mL. Moreover, PV-Q5 increased bacterial cell membrane permeability and ruptured bacteria cell membranes, as revealed by transmission electron microscopy. Circular dichroism analysis showed that the conformation of PV-Q5 was a random coil in phosphate-buffered saline and α-helical in sodium dodecyl sulfate, which is conducive for interaction with bacteria cell membranes. These findings indicated that PV-Q5 could find potential use in food preservation to control foodborne pathogenic bacteria. Full article

Fermentative and antioxidative characteristics of Godulbaegi kimchi (LGK), a traditional, fermented Korean food, were conducted. For the study, LGK kimchi was made of Godulbaegi kimchi with pepper powder, salted shrimp, refined salt, green onions, and so on, and fermented at 5C for 6 months. The pH was decreased, and total acidity was increased during fermentation. Furthermore, lactic acid bacteria and yeast were increased, while the total viable count was decreased. The LGK showed the highest DPPH-scavenging activity, phenol content, and nitrite-scavenging activity with methanol extract among methanol, ethanol, and water. In addition, we screened strains among LGK kimchi with high antimicrobial activity and isolated them. We tested antimicrobial activity for 20 lactic acid bacteria, and we separated and identified nine strains of lactic acid bacteria with high antimicrobial activity. Given these results, LGK is expected to be an effective food in considerable antioxidative activity with an antimicrobial effect. These results are expected to serve as basic data for the study of Godulbaegi kimchi. Full article

Quality changes of salted shrimp paste, one of the most popular traditional Thai fermented food ingredients, stored in different packaging containers including polypropylene containers (PP), polyethylene terephthalate containers (PET), glass jar containers (GJ) as well as LLDPE/Nylon vacuum bags (VB) at room temperature (28 ± 1 °C) for 15 months were studied. The relationship between quality attributes (i.e., volatiles, browning index (A₄₂₀), biogenic amines, TBARS) and consumer acceptability as indicated by sensory scores were also investigated using principal component analysis (PCA). During storage, some desirable quality characteristics of shrimp paste were improved as indicated by the higher sensory scores of all samples when stored for 6 months, compared with the sample at day 0 (p ≤ 0.05). However, further changes in all compositions when extended storage time can conversely diminish those desirable characteristics and led to lowering consumers’ acceptability. In this study, GJ seem to be the most potential packaging for preserving original products’ quality during storage for this product since it exhibited the lower rate of quality changing than others throughout the storage. Conversely, VB exhibited unique volatiles and microbial profiles, compared with others, which led to the lowest sensory scores at all period test (p ≤ 0.05), implying that vacuum conditions may not be suitable for the storage of this product. Moreover, based on PCA results, the intensity of nitrogen-containing compounds correlated well with sensory acceptability, particularly flavor-likeness. Our study provides useful knowledge for understanding the different quality characteristics, particularly flavors, associated with different packaging containers during prolonged storage of salted shrimp paste. Full article

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. Full article

The aim of this work was to reuse a fish processing waste, shrimp head powder (SHP), for the production of prodigiosin (PG) via microbial technology and to assess its potential bioactivities. PG was produced in a 12 L-bioreactor system, and the highest PG productivity of 6310 mg L⁻¹ was achieved when Serratia marcescens CC17 was used for fermentation in a novel designed medium (6.75 L) containing 1.5% C/N source (SHP/casein = 9/1), 0.02% K₂SO₄, ans 0.025% Ca₃(PO₄)₂, with initial pH 7.0, and fermentation was performed at 28 °C for 8 h. The purified PG showed moderate antioxidants, efficient anti-NO (anti-nitric oxide), and acetylcholinesterase (AChE) inhibitory activities. In a docking study, PG showed better binding energy scores (−12.3 kcal/mol) and more interactions (6 linkages) with several prominent amino acids in the biding sites on AChE that were superior to those of Berberine chloride (−10.8 kcal/mol and one linkage). Notably, this is the first investigation using shrimp heads for the mass bioproduction of PG with high productivity, and Ca₃(PO₄)₂ salt was also newly found to significantly enhance PG production by S. marcescens. This study also provided available data on the anti-NO and anti-AChE effects of PG, especially from the docking simulation PG towards AChE that was described for the first time in this study. The above results suggest that SHP is a good material for the cost-effective bioproduction of PG, which is a potential candidate for anti-NO and anti-Alzheimer drugs. Full article

Recently, microbial prodigiosin (PG) has received much attention due to its numerous beneficial applications. The aim of this study was to establish the bioprocessing of marine chitinous wastes (MCWs) for the cost-effective preparation of PG. Of the MCWs, demineralized shrimp shell powders (de-SSP) were found to be a potential source of carbon/nitrogen (C/N) for PG production by bacterial fermentation using Serratia marcescens strains. Further, PG scale-up production was investigated in a 15 L bioreactor system, and the highest yield (6200 mg/L) was achieved during fermentation using 5 L of a novel-designed culture broth that included 1.60% C/N sources (a de-SSP/casein ratio of 7/3), 0.02% K₂SO_4, and 0.05% K₂HPO₄, with an initial pH of 6–7. Fermentation was conducted in the dark at 27.5 °C for 8.0 h. This study was the first to report on the utilization of shrimp wastes for cost-effective, large-scale (5 L/pilot) PG production with high productivity (6200 mg/L) in a short cultivation time. The combination of 0.02% K₂SO₄ and 0.05% K₂HPO₄ was also found to be a novel salt composition that significantly enhanced PG yield. The red compound was purified and confirmed as PG after analyzing its HPLC profile, mass, and UV/vis spectra. The purified PG was then tested for its bioactivities and showed effective anticancer activities, moderated antioxidant activities, and novel anti-NO effects. Full article