Salt plays an important role in giving saltiness and adjusting taste in daily life. However, excessive intake of salt will cause certain harm to the body. Therefore, it has become an urgent need to develop new food processing strategies to reduce salt without reducing saltiness. In present study, Maillard reaction was employed to improve the flavor of Katsuwonus pelamis hydrolysates (KPSPs) with saltness. The change of flavor was measured by electronic tongue and sensory evaluation. After Maillard reaction of KPSPs and xylose, the bitter and other unpleasant flavor of the hydrolysates were reduced, whereas the saltiness and acceptability were enhanced significantly. The content of bitter amino acids of the Maillard reaction products of KPSPs (M-KPSPs) was reduced. Due to the covalent bonding between the peptide chain and the sugar molecules, the intrinsic fluorescence intensity was weakened with a redshift of the maximum emission wavelength, indicating that the tryptophan microenvironment became looser and more hydrophilic. The decrease in the composition of bitter amino acids and a change in the secondary structure of the peptides might lead to the change in the perception of flavor. The findings suggested that Maillard reaction affected the flavor characteristics, which provided a new idea for the improvement on non-Na⁺ saltiness of healthy food additives via Maillard reaction between protein hydrolysate and reducing sugars.

Pseudomonas aeruginosa (P. aeruginosa), recognized for its biofilm production and secretion of virulence factors, posing a severe threat in areas such as clinical infections, food contamination, and marine biofouling. To address this, a new type of zinc-chelating peptide (CSSP-Zn) was prepared from crimson sapper scales peptides (CSSP) and goslarite, and its antibacterial and anti-quorum-sensing activities toward P. aeruginosa PAO1 were exploited. Results indicated that CSSP-Zn induced planktonic strain PAO1 membrane injury via inhibiting expression levels of cell integrity genes, targeting microbial-specific membrane constituents, disrupting proton motive force, and causing metabolic disturbances. Meanwhile, CSSP-Zn decreased virulence factors pyocyanin, protease, and rhamnolipid secretion, while considerably inhibiting quorum sensing-related genes (las, pqs, and rhl) expression and decreasing bacterial abundance and pathogenicity in fish models. Moreover, CSSP-Zn not only effectively hindered biofilm formation but also disassembled preformed ones, thus disrupting biofilm topology. Taken together, utilizing food byproducts to obtain CSSP-Zn could help recycle food resources, and provide insight into controlling planktonic and biofilm strain PAO1 contamination.

Identification of natural substances with antioxidant properties is ongoing research for addressing issues related to oxidative stress especially attributed to environmental effects. Our previous study demonstrated that Lateolabrax japonicus peptides (LPH), rich in Glu, Gly, and hydrophobic amino acids, exhibited remarkable antioxidant activity in vitro, with though its action mechanism yet to be revealed. Therefore, to assess the in vivo antioxidative properties of LPH, we employed H₂O₂ to generate oxidative stress in Drosophila melanogaster model. Results indicated that LPH significantly prolonged the lifespan of Drosophila subjected to oxidative stress mostly mediated via LPH's enhancement of the antioxidant defense system and intestinal functions. Antioxidant effects were manifested by a decrease in malondialdehyde (MDA) levels, elevated superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, decreased levels of reactive oxygen species (ROS) in intestinal epithelial cells, and the preservation of intestinal length. LPH effectively controlled the excessive proliferation and differentiation of oxidative stress-induced Drosophila intestinal stem cells. At the gene level, LPH upregulated the expression of antioxidant-related Nrf2 genes while concurrently downregulated mTOR expression level. Furthermore, high-throughput 16S rDNA sequencing revealed that the addition of LPH significantly influenced the diversity and abundance of the intestinal microbiota in H₂O₂-induced Drosophila. These findings provide a deeper understanding of the antioxidative mechanism of LPH, suggesting its potential applications in food industry and to be assessed using other in vivo oxidative stress models.

The purpose of this study was to explore the potential of the development and application of Paecilomyces hepiali, a fungus with edible and medicinal value, as a foodborne antioxidant and anti-aging agent. Its n-butanol extract (PHE) from rice cultures was selected for anti-aging experiment because of significant free radical scavenging activity in vitro. In vivo, PHE could significantly prolong the mean lifespan, 50 % survival days, and the maximum lifespan of Drosophila on a high-fat diet. It is amazing that the mean lifespan increased from 19.1 days to 32.9 days, 50 % survival days increased from 15.7 days to 34.3 days, and the maximum lifespan extended from 44.7 days to 52.7 days, when the high-fat female Drosophila model was fed with 10 μg/mL PHE. Further research showed that PHE reduced the accumulation of peroxide products and increased the activity of antioxidant enzymes. Then, through antioxidant activity tracking, dimerumic acid (compound 1, the IC₅₀ value of 3.4 μg/mL on DPPH free radicals scavenging activity), 4, 5-dihydroxy-3-methoxypentanoic acid (compound 2, new compound), and thymidine (compound 3) were isolated from PHE. It is worth mentioning that dimerumic acid, the major antioxidant compound of PHE (content up to 3 %), was discovered in P. hepiali for the first time. It was concluded that PHE showed excellent anti-aging activity at a very low concentration on fat diet-induced high fat Drosophila melanogaster, and dimerumic acid may be its main material basis. These results indicated that PHE had the potential to be developed as antioxidant and anti-aging agent in the healthcare industry.

Paecilomyces hepiali is a fungus with edible and pharmaceutic value, isolated from Ophiocordyceps sinensis. Its main bioactive constituents contain alkaloids, cyclic dipeptides, steroids, organic acids, and polysaccharides. Due to the huge development potential of P. hepiali in the field of food and medicine, it has been developed into a variety of products that cater to the needs of the public. In this paper, the chemical constituents and their pharmacological effects of P. hepiali are reviewed, which can provide reference for the development and application of P. hepiali.