In-depth discovery and taste presentation mechanism studies on umami peptides derived from fermented sea bass based on peptidomics and machine learning.

Umami peptides originating from fermented sea bass impart a distinctive flavor to food. Nevertheless, large-scale and rapid screening for umami peptides using conventional techniques is challenging because of problems such as prolonged duration and complicated operation. Therefore, we aimed to screen fermented sea bass using peptidomics and machine learning approaches. The taste presentation mechanism of umami peptides was assessed by molecular docking of T1R1/T1R3. Seventy umami peptides identified in fermented sea bass predominantly originated from 28 precursor proteins, including troponin, myosin, motor protein, and creatine kinase. Six umami peptides with the lowest energies formed stable complexes by binding to T1R3. SER170, SER147, GLN389, and HIS145 are critical binding sites for T1R1/T1R3. Four dominant interacting surface forces were identified: aromatic interactions, hydrogen bonding, hydrophilic bonds, and solvent-accessible surfaces. Our study unveils a method to screen umami peptides efficiently, providing a basis for further exploration of their flavor in fermented sea bass.

Cooperative combination of non-targeted metabolomics and targeted taste analysis for elucidating the taste metabolite profile and pathways of traditional fermented golden pompano.

Fermentation plays a key role in taste formation in traditional fermented golden pompano and involves a series of complex metabolic reactions. Indeed, the taste profile of fermented golden pompano exhibits remarkable variation during early fermentation. Herein, nutritional fingerprinting (proteins, amino acids, lipids, etc.) was applied to discriminate the various biomolecular changes involved in golden pompano fermentation. Among the differential metabolites, amino acids, small peptides, lipids, and nucleotides were considered taste-related compounds. An increase in the amino acid content was observed during fermentation, while the peptide content decreased. Glutamic acid, alanine, and lysine had the highest taste activity values and were the main contributors to taste formation. Metabolic pathway enrichment analysis revealed that taste formation was primarily associated with alanine, aspartate, and glutamate metabolism. These findings provide a deeper understanding of taste mechanisms and establish a basis for the targeted regulation of taste formation in the fermented fish industry.

Isolation and characterization of antioxidant peptides from oyster (Crassostrea rivularis) protein enzymatic hydrolysates.

Peptides from oysters have several bioactive functions. In this study, we identified antioxidant peptides from oysters (Crassostrea rivularis) and investigated their structure-function relationship. We used an 8 kDa molecular-weight (MW) cut-off membrane and semiprep reversed-phase liquid chromatography to collect five peptides (F1-F5) and identified the highest-abundance ion-peak sequences AWVDY (F1), MSFRFY(F2), EPLRY(F3), RKPPWPP(F4), and YAKRCFR(F5) having MWs of 652, 850, 676, 877, and 943 Da, respectively, using ultra-performance liquid chromatography-quadrupole/time-of-flight tandem mass spectrometry. These peptides exhibited high antioxidant activities, similar to butylated hydroxytoluene, reduced glutathione, and ascorbic acid. F5 demonstrated the highest scavenging activity for DPPH radicals (IC50 = 21.75 µg/ml), hydroxyl radicals (IC50 = 18.75 µg/ml), and superoxide radicals (IC50 = 11.00 µg/ml), while F3 demonstrated the highest reducing power. Furthermore, F5 significantly protected Caco-2 cells from H2O2-induced oxidative damage. These results suggest that the antioxidant peptide F5 is a promising food additive that protects against oxidative damage.

Anti-inflammatory and anti-nociceptive activities of Sipunculus nudus L. extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Sipunculus nudus has long been employed as traditional Chinese medicine in folk remedies for the treatment of carbuncles, tuberculosis and nocturia, regulating the functions of stomach and spleen, as well as for the restoration to health in debilities caused by various pathogens and aging. Decoction of Sipunculus nudus has traditionally been used to remedy sternalgia in folk medicine. AIM OF THE STUDY: This study aimed to assess the anti-inflammatory and anti-nociceptive activity of the water extract from Sipunculus nudus. MATERIALS AND METHODS: The water extract from the body wall of Sipunculus nudus was obtained with the yield of 14.1%. The anti-inflammatory effect in six animal models and anti-nociceptive effect in two animal models of the water extract were evaluated by oral for the study. RESULTS: Pretreatment with the extract (at the dose of 50, 100 and 200 mg/kg) produced significant dose-dependent anti-inflammatory and anti-nociceptive effects. At 200 mg/kg dose, the inhibition ratio of the extract on carrageenan-induced rat hind paw oedema, dextran-induced rat paw oedema, cotton pellet granuloma in rats, carrageenan-induced peritonitis and acetic acid-induced vascular permeability were 59.2%, 51.0%, 53.1%, 42.5%, 50.8%, better than that of indomethacin (5 mg/kg) 49.5%, 50%, 44.4%, 37.6%, 46.8%, respectively. The inhibition ratio of the extract (200 mg/kg dose) on xylene-induced mouse ear oedema was 61.5%, lower than 63.7% for indomethacin (5 mg/kg). At 200mg/kg, the extract decreased number of writhing 52.3% in acetic acid-induced writhing model and increased the response latency 25.24% in hot plate test. CONCLUSIONS: The water extract from the body wall of Sipunculus nudus possesses excellent anti-inflammatory activity as well as peripheral and central analgesic properties.