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The inhibition of dipeptidyl peptidase-IV (DPP-IV) is a promising approach for regulating the blood glucose levels in patients with type 2 diabetes (T2D). Oysters, rich in functional peptides, contain peptides capable of inhibiting DPP-IV activity. This study aims to identify the hypoglycemic peptides from oysters and investigate their potential anti-T2D targets and mechanisms. This research utilized virtual screening for the peptide selection, followed by in vitro DPP-IV activity assays to validate the chosen peptide. Network pharmacology was employed to identify the potential targets, GO terms, and KEGG pathways. Molecular docking and molecular dynamics simulations were used to provide virtual confirmation. The virtual screening identified LRGFGNPPT as the most promising peptide among the screened oyster peptides. The in vitro studies confirmed its inhibitory effect on DPP-IV activity. Network pharmacology revealed that LRGFGNPPT exerts an anti-T2D effect through multiple targets and signaling pathways. The key hub targets are AKT1, ACE, and REN. Additionally, the molecular docking results showed that LRGFGNPPT exhibited a strong binding affinity with targets like AKT1, ACE, and REN, which was further confirmed by the molecular dynamics simulations showcasing a stable peptide–target interaction. This study highlights the potential of LRGFGNPPT as a natural anti-T2D peptide, providing valuable insights for potential future pharmaceutical or dietary interventions in T2D management. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of glazing with sodium polyacrylate (SP) and D-sodium erythorbate (DSE) on the quality changes of squid during frozen storage. Frozen squid samples were randomly divided into seven groups: (1) CK (unglazed); (2) WG (distilled water-glazed); (3) SG (0.1% SP -glazed); (4) SG-1DSE (0.1% SP with 0.1% DSE -glazed); (5) SG-3DSE (0.1% SP with 0.3% DSE-glazed); (6) SG-5DSE (0.1% SP with 0.5% DSE-glazed); (7) WG-1DSE (0.1% DSE-glazed). The efficacy of the different coatings was evaluated using various indicators, such as water holding capacity (WHC), pH value, low field nuclear magnetic resonance (LF-NMR), color, malondialdehyde (MDA) content value, free amino acids (FAAs) content, intrinsic fluorescence intensity (IFI) and the total sulfhydryl content (SH) content. Intrinsic fluorescence intensity (IFI) and low field nuclear magnetic resonance (LF-NMR) were used as fast monitoring techniques to monitor changes in quality of squid samples. The results showed that compared with the CK and WG groups, coating with either SG or DSE alone resulted in reduced rate of moisture loss (p < 0.05), lipid oxidation (p < 0.05) protein degradation (p < 0.05) and prolonged its shelf-life. The combination of glazing treatment with SG and DSE (groups SG-1DSE, SG-3DSE and SG-5DSE) further improved the protective effects of coating, particularly in the SG-3DSE group. Therefore, the glazing of SG-3DSE is recommended to be used to control the quality of frozen squid and to prolong its shelf-life during frozen storage. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effect of dehydration on the water migrating property and protein changes of large yellow croaker during frozen storage. A freeze-dryer was used to accelerate experiments, which was isolated from oxygen and excluded the effects of protein oxidation. After dehydration time (3, 9, 18, and 30 h) for both fast- and slow-freezing samples, the results showed that the ice sublimation of samples containing small ice crystals was faster than that of samples containing large ice crystals in the early stages of dehydration, but in the latest stage, there was an opposite trend. The results indicated that dehydration reduced the water freedom degrees and water–protein interaction. At the same time, dehydration had a significant effect on protein secondary and tertiary structures. The significant increase in surface hydrophobicity and particle size indicated that dehydration exacerbated myofibrillar protein aggregation. The ΔH1 values (from 1.275 to 0.834 J/g for slow-freezing group and from 1.129 to 0.855 J/g for fast-freezing group) decreased gradually as the dehydration time extended, indicating the decrease in protein thermal stability. Additionally, significant protein degradation occurred when the water content of the sample decreased to a certain level. This study showed that ice crystal size had an important effect on the rate of ice sublimation, and the occurrence of dehydration during frozen storage accelerated the water loss and the decrease in protein stability. [ABSTRACT FROM AUTHOR]

Although freezing has been used to delay the deterioration of product quality and extend its shelf life, the formation of ice crystals inevitably destroys product quality. This comprehensive review describes detailed information on the effects of ice crystals on aquatic products during freezing storage. The affecting factors (including nucleation temperature, freezing point, freezing rate, and temperature fluctuation) on the size, number, distribution, and shape of ice crystals are also elaborated in detail. Meanwhile, the corresponding technologies to control ice crystals have been developed based on these affecting factors to control the formation of ice crystals by inhibiting or inducing ice crystallization. In addition, the effects of ice crystals on the water, texture, and protein of aquatic products are comprehensively discussed, and the paper tries to describe their underlying mechanisms. This review can provide an understanding of ice crystallization in the aquatic products during freezing and contribute more clues for maintaining frozen food quality. [ABSTRACT FROM AUTHOR]