• An open-source, lightweight and efficient tool, PeposX-Exhaust, was developed for short peptide identification. • The algorithm was proved of high accuracy with the adjusted accuracy rate reaching 98.55% for the known peptide mixtures. • Much higher accuracy and better performance was obtained by the tool rather than the other tools. • Hundreds of short peptides were efficiently identified from the food-derived protein hydrolysates.

Longan (Dimcarpus longan Lour.) is a kind of traditional fruit used as a medicine and a food. Fresh longan is primarily consumed as a fruit, whereas dried longan is commonly employed for medicinal purposes. The differences in the immunomodulatory activities and mechanisms of polysaccharides between dried and fresh longan remain unclear. The present study comparatively analyzed the mechanisms of macrophage activation induced by polysaccharides from dried (LPG) and fresh longan (LPX). The results revealed that LPG and LPX differentially promoted macrophage phagocytosis and the secretion of NO, TNF-α, and IL-6. RNA-seq analysis revealed that LPG and LPX differentially affected gene expression in macrophages. The LPG treatment identified Tnf and chemokine-related genes as core genes, while myd88 and interferon-related genes were the core genes affected by LPX. A comprehensive analysis of the differentially expressed genes showed that LPG initiated macrophage activation primarily through the TLR2/4-mediated TRAM/TRAF6 and CLR-mediated Src/Raf1 NF-κB signaling pathways. LPX initiated macrophage activation predominantly via the CLR-mediated Bcl10/MALT1 and NLR-mediated Rip2/TAK1 MAPK and NF-κB signaling pathways. Interestingly, the non-classical NF-κB signaling pathway was activated by polysaccharides in both dried and fresh longan to elicit a slow, mild immune response. LPG tends to promote immune cell migration to engage in the immune response, while LPX facilitates antigen presentation to promote T cell activation. These findings contribute insights into the mechanisms underlying the differences in bioactivity between dried and fresh longan and their potential applications in immune-enhancing strategies and functional-food development.

In this study, the compositional shifts in free and bound phenolic compounds of Morinda citrifolia L. (Noni) processed by different drying methods were investigated. Twenty-seven phenolic compounds, predominantly rutin and quinic acid, were discovered in fresh Noni fruit. Vacuum freeze-drying retained the highest free phenolic content, with rutin (1809.83 mg/kg DW) and quinic acid (198.72 mg/kg DW) as the primary constituents, while bound phenolics were dominated by benzoic acid (35.56 mg/kg DW). Hot-air drying reduced the free phenolics by 51.59% (80% methanol) and the bound phenolics (base hydrolysis) by 35.55%, with a significant degradation of rutin and quinic acid. Microwave drying similarly decreased the free phenolics, though the caffeic acid increased to 46.45 mg/kg DW due to the thermal stability. Bound phenolics showed the highest content (alkaline hydrolysis) in fresh fruits, primarily benzoic acid (220.67 mg/kg DW) and rutin (77.02 mg/kg DW), surpassing the acid/enzyme methods. While vacuum freeze-drying effectively preserved the free phenolics, thermal methods (hot-air/microwave drying) promoted the release of quercetin (free phenols) and 3,4-dihydroxybenzoic acid (bound phenols). The findings of this study elucidate the species-specific compositional dynamics of phenolic compounds under different drying regimes, while providing quantitative guidelines for advancing the understanding of the underlying health-promoting phytochemical profiles of Noni.

Influenced by various physical, chemical, and microbial factors, the aging process of Citri Reticulatae ‘Chachiensis’ Pericarpium (CRCP) poses a complex scientific challenge. Drawing inspiration from the perspective of traditional Chinese medicine, volatile oils were extracted from CRCP aged 1, 3, 5, and 7 years by steam distillation and subsequently analyzed by GC-MS. The results revealed that the relative percentage of 4-vinylguaiacol (4-VG) increased progressively with aging. Nineteen volatile oil components were further assessed for their glucose metabolism-enhancing activities, with 4-VG emerging as a key active compound. Notably, 4-VG remarkably enhanced insulin-stimulated glucose uptake in C2C12 myotubes. Moreover, 4-VG demonstrated potent antihyperglycemic effects by upregulating IRS-1/Akt/GSK-3β phosphorylation in the insulin signaling pathway on a high-fat diet and STZ-induced diabetic mouse model. In addition, the metabolic pathway of 4-VG, from ferulic acid and then to vanillin and guaiacol, was verified via HPLC-UV, metabolomics, and microbiome analyses, which confirmed the microbial conversion of 4-VG within CRCP. The metabolic pathway was ultimately validated by isolating and identifying Priestia aryabhattai, Bacillus velezensis, and Aspergillus fumigatus from CRCP, with further in vitro culture and biotransformation experiments confirming its functionality and efficiency. These findings provide new insights and experimental evidence that deepen our understanding of the aging process of CRCP.