The peptide MOp3 from Moringa oleifera seeds has been reported to have good antimicrobial activity against Staphylococcus aureus, but its specific antimicrobial effect is still unclear. Therefore, ...the present study aimed to investigate the antibacterial properties of MOp3 against S. aureus in terms of membrane damage, intracellular key enzyme activities, cell apoptosis induction, and metabolite changes, and evaluate its antibacterial ability in pasteurized milk. The results showed that MOp3 caused irreversible membrane damage to S. aureus cells by increasing the membrane permeability and decreasing the activity of intracellular AKP, LDH, and ATPase. Moreover, ROS accumulation, DNA fragmentation, and nuclear rupture in the S. aureus cells treated with MOp3 induced cell apoptosis. The metabolomics analysis revealed that 46 different metabolites were involved in peptidoglycan synthesis, amino acid metabolism, glycerophospholipid metabolism, nucleotide metabolism, and energy metabolism, that can affect cell wall biosynthesis, cell membrane structure, and genetic material expression. Besides, MOp3 inhibited the growth of S. aureus in the infecting pasteurized milk which storaged at 25 °C and 4 °C for 7 days. Overall, these findings provided deeper insights into antibacterial properties of MOp3 against S. aureus and its application in food preservation.
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•The peptide MOp3 caused irreversible membrane damage to S. aureus cells.•MOp3 decreased the activity of intracellular AKP, LDH, and ATPase in S. aureus cells.•Mop3 induced apoptosis in S. aureus cells.•Metabolomics analysis revealed the multiple mechanisms of MOp3 against S. aureus.•Mop3 inhibited the growth of S. aureus in the infecting pasteurized milk.
The combination of natural antimicrobial peptide BCp12/phenyllatic acid (BCp12/PLA) presents a more efficient antibacterial effect, but its antibacterial mechanism remains unclear. This study studied ...the synergistic antibacterial mechanism of BCp12 and PLA against S. aureus. The results demonstrated that the BCp12/PLA combination presented a synergistic antibacterial effect against S. aureus, with a fractional inhibitory concentration of 0.05. Furthermore, flow cytometry and scanning electron microscope analysis revealed that BCp12 and PLA synergistically promoted cell membrane disruption compared with the group treated only with one compound, inducing structural cell damage and cytoplasmic leakage. In addition, fluorescence spectroscopy analysis suggested that BCp12 and PLA synergistically influenced genomic DNA. BCp12 and PLA targeted enzymes related to peptidoglycan and DNA synthesis and interacted by hydrogen bonding and hydrophobic interactions with mur enzymes (murC, murD, murE, murF, and murG), dihydrofolate reductase, and DNA gyrase. Additionally, the combined treatment successfully inhibited microbial reproduction in the storage of pasteurized milk, indicating that the combination of BCp12 and PLA can be used as a new preservative strategy in food systems. Overall, this study could provide potential strategies for preventing and controlling foodborne pathogens.
•BCp12 combined with PLA has synergistic antibacterial effect.•BCp12 combined with PLA destroyed the integrity and permeability of cell wall membrane.•BCp12 combined with PLA interfered with the synthesis of peptidoglycan.•BCp12 combined with PLA affected DNA synthesis and self-replication.•The BCp12 combined with PLA is a new and efficient food preservative.
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•Whey hydrolysates from rubing cheese by-product have α-glucosidase inhibitory activity.•Peptides YPVEPF, VPYPQ, and LPYPY were identified in rubing whey hydrolysates.•YPVEPF is an ...amphipathic peptide and interacted with α-glucosidase.•YPVEPF had negligible hemolytic activity and promoted glucose consumption in HepG2 cells.•YPVEPF is a novel hypoglycemic peptide with potential application in functional foods.
The by-product of Chinese rubing cheese is rich in whey protein. Whey hydrolysates exhibit good hypoglycemic activity, but which specific peptide components are responsible for this effect have not yet been investigated. Herein, the α-glucosidase inhibitory activity of the ultrafiltered fraction (<3 kDa) of rubing cheese whey hydrolysates was evaluated with the inhibition rate of 37.89 %. In addition, peptide identification was conducted using LC-MS/MS, and three peptides YPVEPF, VPYPQ, and LPYPY were identified. Among these, YPVEPF had higher α-glucosidase inhibitory activity (IC50 = 3.52 mg/mL) and interacted with α-glucosidase via hydrogen bonding and hydrophobic forces. YPVEPF was characterized as an amphipathic peptide rich in antiparallel (50.50 %) and random coil (35.20 %) structures, as well as showed good tolerance to gastrointestinal digestion and incubation under the temperature range of 20–80 °C. Notably, YPVEPF activity increased in the presence of Al3+ and Fe3+, as well as within the pH range of 2.0–6.0. Furthermore, YPVEPF had negligible hemolytic activity at a concentration of 1.0 mg/mL, no toxicity at concentrations below 0.5 mg/mL, and significantly promoted glucose consumption in HepG2 cells (p < 0.0001). Collectively, these findings indicate the potential of YPVEPF to be used as a novel hypoglycemic peptide in functional foods.
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•The latest discovery on the digestive properties and peptide profile of rubing cheese.•Rubing cheese peptides exhibited antioxidant effect, ACE inhibition and α-glucosidase ...inhibitory.•Generation of potentially bioactive peptides is affected by acidification technology changes.•Fermentation-acidification improved digestibility and produce more bioactive peptides.
Rubing cheese is a traditional Chinese Protected Designation of Origin (PDO) cheese consumed for more than six hundred years, but to date, the digestion properties and peptide profiling during simulated gastrointestinal digestion are still uncertain. This study aimed to investigate the effects of traditional direct acidification technology (TRB) and fermentation acidification technology on digestion properties and peptide profiling of rubing cheese (FRB) proteins after simulated gastrointestinal digestion by protein digestomics, coupled with bioinformatic in silico analyses to identify potential bioactive peptides. The results demonstrated that FRB could significantly improve the in vitro digestibility, protein degradation, and polypeptide content than TRB (P ＜ 0.05). Furthermore, a total of 369 and 332 peptides were identified in FRB- and TRB-pancreatic digests, respectively, using LC-MS/MS. FRB could release more low molecular weight peptides of 400–1200 Da from α-casein and β-casein after digestion. These low peptides included 16 reported potential ACEIPs (angiotensin I-converting enzyme inhibitory peptides), 11 dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides, and 6 antioxidant peptides, while TRB contained more than the reported potential antimicrobial peptides (10). In vitro activity determination showed that FRB had significantly higher ACEI, α-glucosidase inhibitory, and antioxidant activities than TRB during the entire digestion time (P ＜ 0.05), which was correlated to the reported potential bioactive peptides released during the digestion of FRB. Our study is the most comprehensive protein digestomic analysis of Chinese rubing cheese to date and provides a new positive outlook on rubing cheese consumption.
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•Duroc × (Landrace × Yorkshire) pig ham peptides are mainly derived from myosin and actin.•YDEAGPSIVH is a novel peptide with antioxidant and α-glucosidase inhibitory activity.•The ...YDEAGPSIVH has good gastrointestinal digestion stability.•Hydrogen bonding and hydrophobic interactions drive YDEAGPSIVH binding to α-glucosidase.•YDEAGPSIVH docked to α-glucosidase formed stable and compact conformations.
Duroc × (Landrace × Yorkshire) pigs are popular in the Chinese market because of their rapid growth, leanness, and economic value. Despite their widespread use in dry-cured ham processing, there is a lack of research on the bioactive peptides of Duroc × (Landrace × Yorkshire) pig ham (DLYH). This study aimed to investigate the presence of peptides with antioxidant and α-glucosidase inhibitory activities in DLYH using peptidomics and in silico analysis. A total of 453 peptides were identified from DLYH, originating mainly from myosin, actin, and the EF-hand domain-containing protein. Notably, two peptides, YDEAGPSIVH (YH10) and FAGDDAPRAVF (FF11), emerged as novel bioactive peptides with antioxidant and α-glucosidase inhibitory activities. Among these peptides, YH10 exhibited a high DPPH radical scavenging activity (IC50 = 1.93 mM), ABTS radical scavenging activity (IC50 = 0.10 mM), α-glucosidase inhibitory activity (IC50 = 2.13 mM), and good gastrointestinal tolerance. Molecular docking analysis showed that YH10 was bound to the ABTS and DPPH radicals and the active site of α-glucosidase (3A4A) primarily through hydrogen bonding and hydrophobic interactions. Furthermore, molecular dynamics (MD) simulation indicated that the YH10-3A4A complexes maintained stable and compact conformations. In conclusion, our findings indicated that peptide YH10 derived from DLYH possesses bifunctional properties of α-glucosidase inhibition and antioxidant activity, which could be beneficial for maintaining ham quality and promoting human health.
The prevalence of Listeria monocytogenes in bovine milk from different regions of Yunnan Province, Southwest China, was investigated. The isolated strains were genotyped using pulsed-field gel ...electrophoresis (PFGE), and their virulence and antibiotic resistance potential analysed with whole-genome sequencing (WGS). A total of 8 L. monocytogenes strains were isolated from 4 out of 161 samples, with a detection rate of 2.48%. All strains were at least resistant to one antibiotic, and the majority of strains (75%) were multi-antibiotic resistant. The 8 strains were clustered into 3 pulsotypes, and each pulsotype contained only strains isolated from the same geographical area. One strain was selected from each pulsotype for WGS, and it was found that a total of 99 antibiotic resistance genes and 83 virulence genes were detected from the 3 strains, respectively, which indicated that L. monocytogenes isolated from bovine milk have strong antibiotic resistance and virulence potential.
The mechanism of goat milk (GM) flavor improvement based on lipid changes requires understanding. According to sensory evaluation results, the texture, taste, appearance, aroma, and overall ...acceptability score of Guishan fermented goat milk (GMF) were higher than those of GM. In total, 779 lipid molecules and 121 volatile compounds were formed from the metabolite–lipid level in the GM and GMF, as determined through lipidomics and gas chromatography–mass spectrometry. The key volatile flavor compounds in the GMF were (E,E)-2,4-decadienal, ethyl acetate, acetoin, 2,3-pentanedione, acetic acid, and 2,3-butanedione. Of them, 60 lipids significantly contributed to the flavor profiles of the GMF, based on the correlation analysis. The triacylglycerides (TAGs) 12:0_14:0_16:0 and 13:0_13:0_18:2 contributed to aroma retention, while TAG and phosphatidylethanolamine were identified as key substrates for flavor compound formation during fermentation. Lipids associated with glycerophospholipid and linoleic acid metabolism pathways significantly affected volatile compound formation in the GMF. This study provides an in-depth understanding of the lipids and flavors of the GMF, and this information will be useful for the development of specific GMF products.
•Lipid changes affect flavor formation in fermented goat milk (GMF).•Acetoin, 2,3-pentanedione, and 2,3-butanedione are abundant in GMF.•TAG (12:0/14:0/16:0) and TAG (13:0/13:0/18:2) contribute to aroma retention in GMF.•Flavor compounds are derived from glycerophospholipid and linoleic acid pathways.•Lipid markers are identified to improve the flavor of GMF.
The aims of this study were to investigate the roles of free fatty acid (FFA) profiles and oxidation in the formation of characteristic volatile compounds in ham produced from Dahe black (DW) and ...hybrid breed (Yorkshire × Landrace × DW, YLDW; and Duroc × Landrace × Yorkshire, DLY) pigs using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF-MS). Among the three types of hams studied, DW ham exhibited the highest total contents of FFAs (11,088.91 μg/kg), volatile flavor compounds (3750.867 μg/kg), aldehydes and alcohols. A total of 38 FFAs and 80 volatile compounds were identified in the three hams. According to odor activity values, 18 odorant-active compounds, including isovaleraldehyde, heptanal, 2-methylbutyraldehyde, decanal, hexanal, n-octanal, nonanal, 1-octen-3-ol, methional and eucalyptol, which mainly comprised aldehydes and alcohols, were selected for the discriminatory analysis between hams produced from DW, YLDW and DLY pigs. Furthermore, correlation analysis demonstrated that the oxidative decomposition of polyunsaturated fatty acids (i.e., trans-9-octadecenoic, cis-9,12-linoleic, γ-linolenic, α-linolenic, and arachidonic acid) is essential for the formation of volatile characteristics of ham. These results indicated that FFAs and volatile profiles of ham were breed dependent, and that the formation of volatile profiles in ham is closely related to lipid oxidation.
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•Application GC × GC-TOF MS to flavor identification of different types hams.•38 fatty acids and 80 volatile compounds were identified in hams from three pig breeds.•18 odorant-active compounds for ham discrimination were identified.•Aldehydes contributed to fruity and porky aroma in ham of Dahe black pork.•Oxidative of linoleic, linolenic and arachidonic acids contribute to flavor formation in ham.
Rennet, an aspartate protease found in the stomach of unweaned calves, effectively cuts the peptide bond between Phe105-Met106 in κ-casein, hydrolyzing the casein micelles to coagulate the milk and ...is a crucial additive in cheese production. Rennet is one of the most used enzymes of animal origin in cheese making. However, using rennet al.one is insufficient to meet the increasing demand for cheese production worldwide. Numerous studies have shown that plant rennet can be an alternative to bovine rennet and exhibit a good renneting effect. Therefore, it is crucial and urgent to find a reliable plant rennet. Based on our team's research on rennet enzymes of plant origin, such as from Dregea sinensis Hemsl. and Moringa oleifer Lam., for more than ten years, this paper reviews the relevant literature on rennet sources, isolation, identification, rennet mechanism, functional active peptide screening, and application in cheese production. In addition, it proposes the various techniques for targeted isolation and identification of rennet and efficient screening of functionally active peptides, which show excellent prospects for development.
