Ke Zhao

This study aimed to identify novel umami peptides from both natural and enzymatically hydrolyzed peptides from Jinhua ham, and to characterize their properties. Following LC–MS identification, known flavor sequences were annotated using a curated flavor-peptide database containing 2617 known flavor peptides, and potential novel umami peptides were screened through an integrated approach combining multiple machine learning models and LibDock molecular docking. From over 2000 identified peptides, this integrated virtual screening pipeline precisely yielded 10 candidate umami peptides, which were confirmed to possess distinct umami characteristics by sensory evaluation and electronic tongue analysis. These peptides had umami intensities ranging from 2.87 ± 1.38 to 3.90 ± 1.56 and significantly lower taste thresholds (0.1109–0.2634 mg/mL) than that of monosodium glutamate (MSG, 0.3 mg/mL). Subsequent CDOCKER analysis demonstrated significantly stronger binding affinity and stability of these peptides to the T1R1/T1R3 receptor compared with MSG, with -CDOCKER ENERGY values of 78.45–94.95 and -CDOCKER INTERACTION ENERGY values of 56.67–86.71, both significantly higher than those of MSG (22.27 and 46.58, respectively). Hydrogen bonds were identified as the dominant binding force, accounting for over 66% of total interactions, and HIS145 and ARG247 were confirmed as the key residues maintaining the stability of the peptide-receptor complex. Overall, these findings provide mechanistic insight into the umami properties of Jinhua ham peptides and support their potential application in food processing.

Fu brick tea (FT), known for regulating lipid metabolism, was studied to explore its lipid-lowering mechanism by analyzing its effects on gut microbes and adipose tissue. Mice were given chow, high-fat diet (HFD), or HFD + FT aqueous extract (FTE, 400 mg per kg BW). FTE reduced HFD-induced fat deposition, altered gut microbiota (enriched the “glycerolipid metabolism” pathway, reversed HFD-suppressed Firmicutes_bacterium_ASF500), and affected epididymal fat transcriptome (genes enriched in PPAR, glycerolipid/fatty acid metabolism). Four lipid-related genes (Lipf, Lep, Kdsr, Esrra) showed reversed expression patterns, while FTE treatment demonstrated no significant in vitro effects on adipocyte differentiation. FTE may exert lipid-lowering effects via regulating gut microbe/adipose glycerolipid metabolism, with downstream metabolites playing a key role. In summary, FTE may alleviate lipid deposition by elevating Firmicutes_bacterium_ASF500 to regulate dietary derived metabolites, which may enhance Esrra-mediated fatty acid oxidation-related gene expression, thereby improving triglyceride metabolism. Further studies are warranted to elucidate the specific roles and interactions of FTE's potential microbial and gene targets.

Umami peptides were screened and identified from yak bone collagen for the first time by in silico analysis, molecular docking, and electronic tongue. Twenty proteases with known cleavage sites were used for the simulated proteolysis, and results indicated that “pepsin + papain” was the optimal enzymatic strategy for yak bone collagen to generate peptides with potential umami taste. Moreover, 82 novel unreported peptides with umami taste were found from the simulated hydrolysate, among which 9 peptides exhibited high binding affinity with the T1R1/T1R3 receptor (both -CDOCKER energy and CDOCKER interaction energy > 40 kcal/mol) via molecular docking. Subsequently, six novel umami peptides were identified through sensory evaluation and electronic tongue analysis, including VY, VM, SL, SN, VN, and IS (umami sensory score > 5). These peptides were also in silico characterized with high hydrophobicity, good water solubility, non-toxicity, non-allergenicity, good intestinal absorption, and good oral bioavailability. Furthermore, the identified peptides could bind with the key residues (such as HIS281 and LEU304) within the Venus flytrap domain of the T1R3 subunit of receptor T1R1/T1R3 through hydrogen bonds and electrostatic attractions to generate umami perception. This study revealed the mechanism of umami peptides identified from yak bone collagen and provides a novel approach for the development of umami peptides from animal sources.

Yak milk has substantial nutritional value yet remains underutilized for high-value applications. Because yak milk is a rich source of bioactive peptides due to its elevated protein composition, this study investigated yak milk-derived peptides with antioxidant properties and their potential antiaging mechanisms. First, 8 major yak milk proteins were hydrolyzed in silico via BIOPEP. Compared with other enzymes, proteinase K plus subtilisin could generate more antioxidant peptides. Six potential antioxidant peptides were efficiently screened in silico; DGGY presented the strongest hydroxyl radical scavenging rate, and its antioxidant activity was further verified in Caenorhabditis elegans. Additionally, the results of network pharmacology analysis suggested an antiaging role of DGGY, which was validated in C. elegans; specifically, supplementation with DGGY (50 and 300 μg/mL) significantly extended the life span of C. elegans by regulating the expression of related genes (including sod-3, snk-1, daf-16, daf-2, and hsp-16.2). In summary, a novel yak milk protein-derived antioxidant peptide, DGGY, was efficiently screened and found to exert potential antiaging effects. This study provides a method for the high-value utilization of yak milk and novel information for antiaging research.

To understand the impact and mechanism of removing fat and skin tissue on the nutritional metabolism of Chinese dry cured ham, the differential metabolites (DMs) profile between lean ham (LH) and fatty ham (FH) was explored though untargeted metabolomics based on UPLC-MS/MS. The results showed significant differences of the metabolite profiles between FH and LH. A total of 450 defined metabolites were detected, and 266 metabolites among them had significantly different abundances between the two hams, mainly including organic acids and derivatives, and lipids and lipid-like molecules, as well as organoheterocyclic compounds. Furthermore, 131 metabolites were identified as DMs, among which 101 and 30 DMs showed remarkably higher contents in FH and LH, respectively. The further Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that DMs can be mostly enriched in the pathways of ABC transporters, amino acid biosynthesis, protein digestion and absorption, aminoacyl-tRNA biosynthesis, and 2-oxocarboxylic acid metabolism. Moreover, the metabolic network of DMs revealed that the prominent DMs in FH, such as 9(S)-HODE, 9,10-EpOME, 13-Oxo-ODE, L-palmitoyl carnitine, and D-fructose, were primarily involved in the endogenous oxidation and degradation of fat and glycogen. Nevertheless, the dominant DMs in LH, such as 2-isopropylmalic acid, indolelactic acid, and hydroxyisocaproic acid, were mainly the microbial metabolites of amino acids and derivates. These findings could help us understand how fat-deficiency affects the nutritional metabolism of Chinese dry-cured hams from a metabolic perspective.

Hypertension has always posed a severe threat to people’s health. Food-derived angiotensin-converting enzyme (ACE)-inhibitory peptides have the potential to both prevent and treat hypertension. In the current investigation, two ACE-inhibitory peptides (SLPQ and PYVRYL) from goat milk were studied for their endothelial effects using EA.hy926 cells. PYVRYL outperformed SLPQ, yet neither impacted cell survival below 200 μg/mL. Investigation of SLPQ’s impact on EA.hy926 cell expression revealed 114 differentially expressed genes, with 65 downregulated and 49 upregulated. The genes were enriched in cytokine interactions, coagulation cascades, Hippo signaling, and ECM–receptor interaction. Decreased c-x-c motif chemokine ligand 2 (CXCL2), integrin subunit beta 2 (ITGB2), and fbj murine osteosarcoma viral oncogene homologue (FOS) expression and increased secreted phosphoprotein 1 (SPP1) expression may protect endothelial cells from inflammation. Our findings suggest that beyond ACE inhibition, SLPQ aids blood pressure control by influencing endothelial function, paving the way for its use as an antihypertensive food ingredient.

Bioactive peptides (BPs) are protein fragments with beneficial effects on metabolism, physiology, and diseases. This review focuses on proteolytic BPs, which are produced by the action of gut microbiota on proteins in food and have demonstrated to influence the composition of gut microbes. And gut microbiota are candidate targets of BPs to alleviate oxidative stress, enhance immunity, and control diseases, including diabetes, hypertension, obesity, cancer, and immune and neurodegenerative diseases. Despite promising results, further research is needed to understand the mechanisms underlying the interactions between BPs and gut microbes, and to identify and screen more BPs for industrial applications. Overall, BPs offer potential as therapeutic agents for various diseases through their interactions with gut microbes, highlighting the importance of continued research in this area.