This study aimed to reveal the flavor formation and elucidate the key components responsible for the Dahe black pig dry-cured ham. In this study, 172 hams were processed using the traditional method, ...and volatile flavor compounds of 24 hams were investigated using gas chromatography–mass spectrometry (GC–MS) and comprehensive multivariate data analysis. 407 volatile flavor compounds were identified during total ripening process of hams, the amount of flavor components gradually increased with the increase in the processing period, reaching 187 species after ripening for 630 days. However, the principal flavor compounds had formed at 210 days for ripening. The most abundant flavor families were aldehydes and alcohols, moreover, hexanal, 3-methyl-butanal, nonanal, and octanal are the characteristics compounds of ham, which originated from oxidation of fatty acids and degradation of amino acids. Glycosaminoglycan biosynthesis pathway was strongly related with flavor compounds intense changed in 90–150 days.
•407 volatile flavor compounds were found during aging time of Dahe black pig ham.•The principal and characteristic compounds were investigated by metabolomics.•The principal flavor compounds have formed in 210 days of aging stages.•Hexanal, 3-methyl-butanal, nonanal, octanal characterize Dahe black pig ham.•Glycosaminoglycan biosynthesis pathway demonstrated the evolution of initial aging.
This study aimed to investigate the effect of coatings on the quality of ripened dry-cured hams during long-term storage, especially the profile of volatile compounds. The coatings were made up of ...33% palm oil, 16.5% water, 39.7% cassava starch, 6.8% corn starch, 1.6% mono- and diglycerides of fatty acids, 0.6%
tert
-butylhydroquinone (TBHQ), and 1.8% sodium carbonate. The results showed that the moisture content of the coated ham (48.93–49.59%) was higher than that of the noncoated ham (44.37%). The average peroxide value (POV) and
b
* value were lower in the coated hams than in the noncoated hams (5.52 and 8.99 meq/kg, respectively), and the sensory attributes of the coated hams had better overall acceptability scores. The changes in the contents of 39 volatile flavor compounds were evaluated through a multivariate statistical analysis, revealing that 20 identified compounds could be related to the decrease in fat pungent aroma, and most belonged to the long-chain benzene and carboxylic acid family. Meanwhile, 2-nonanone, nonanal, amyl alcohol, and 2-heptanone indicated that they could be used as markers to distinguish between the coated and noncoated groups.
A cysteine peptidase was previously identified from germinated Moringa oleifera seeds, but its milk-clotting properties on bovine caseins was still unclear. In this study, this novel cysteine ...peptidase (MoCP) showed preferential activity on κ-casein (κ-CN), with greater hydrolytic activity compared with calf rennet, whereas weak hydrolysis of α-casein and β-casein made MoCP suitable for application in cheesemaking and may yield various functional peptides. All 3 evaluated caseins were hydrolyzed to form relatively stable peptide bands within 3 h of proteolysis with MoCP. Cleavage sites were determined by gel electrophoresis, liquid chromatography mass spectrometry/mass spectrometry, and peptide sequencing, which revealed that cleavage of κ-CN by MoCP occurred at residue Ile129-Pro130 and generated a 14,895.37-Da peptide. The flocculation reaction between MoCP and κ-CN determined by 3-dimensional microscopy with super-depth of field revealed that the initial 30 min of reaction were key for milk coagulation, which may affect curd yield. Overall, the findings presented herein suggest that the cysteine peptidase from germinated M. oleifera seeds can be considered a promising plant-derived rennet alternative for use in cheese manufacture.
Guishan goats, a unique goat breed in Yunnan Province, have a long history and representation, but their whey protein and function remain unclear. In this study, we carried out a quantitative ...analysis of the Guishan and Saanen goat whey proteome using a label-free proteomic approach. A total of 500 proteins were quantified from the 2 kinds of goat whey proteins, including 463 common proteins, 37 uniquely expressed whey proteins (UEWP), and 12 differentially expressed whey proteins (DEWP). Bioinformatics analysis indicated that UEWP and DEWP were mainly involved in cellular and immune system processes, membrane, and binding. In addition, UEWP and DEWP in Guishan goats participated primarily in metabolism and immune-related pathways, whereas Saanen goat whey proteins were associated mostly with environmental information processing-related pathways. Guishan goat whey promoted the growth of RAW264.7 macrophages more than Saanen goat whey, and significantly reduced the production of nitric oxide in lipopolysaccharide-stimulated RAW264.7 cells. This study provides a reference for further understanding these 2 goat whey proteins and finding functional active substances from them.
Protein lysine malonylation, a novel post-translational modification (PTM), has been recently linked with energy metabolism in bacteria. Staphylococcus aureus is the third most important foodborne ...pathogen worldwide. Nonetheless, substrates and biological roles of malonylation are still poorly understood in this pathogen.
Using anti-malonyl-lysine antibody enrichment and high-resolution LC-MS/MS analysis, 440 lysine-malonylated sites were identified in 281 proteins of S. aureus strain. The frequency of valine in position - 1 and alanine at + 2 and + 4 positions was high. KEGG pathway analysis showed that six categories were highly enriched, including ribosome, glycolysis/gluconeogenesis, pentose phosphate pathway (PPP), tricarboxylic acid cycle (TCA), valine, leucine, isoleucine degradation, and aminoacyl-tRNA biosynthesis. In total, 31 malonylated sites in S. aureus shared homology with lysine-malonylated sites previously identified in E. coli, indicating malonylated proteins are highly conserved among bacteria. Key rate-limiting enzymes in central carbon metabolic pathways were also found to be malonylated in S. aureus, namely pyruvate kinase (PYK), 6-phosphofructokinase, phosphoglycerate kinase, dihydrolipoyl dehydrogenase, and F1F0-ATP synthase. Notably, malonylation sites were found at or near protein active sites, including KH domain protein, thioredoxin, alanine dehydrogenase (ALD), dihydrolipoyl dehydrogenase (LpdA), pyruvate oxidase CidC, and catabolite control protein A (CcpA), thus suggesting that lysine malonylation may affect the activity of such enzymes.
Data presented herein expand the current knowledge on lysine malonylation in prokaryotes and indicate the potential roles of protein malonylation in bacterial physiology and metabolism.
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•A fingerprint profile of milk fermented with L. plantarum L3 was established.•Characteristic metabolites included Thr-Pro, l-creatine, pyridoxine and muramic acid.•Endogenous enzymes ...cleave β- and α-casein to release bioactive peptides.•Six ACE inhibitory, 19 antioxidant and five antimicrobial peptides were identified.•Integrated metabolomics and peptidomics for rapid characterisation of fermented milk.
A novel wild-type Lactiplantibacillus plantarum (L. plantarum) L3 with good fermentation characteristics and protein degradation capacity was isolated from raw milk samples. In this study, the metabolites in milk fermented with L. plantarum L3 were investigated by metabolomic and peptidomics analyses. The metabolomics results revealed that the metabolites in milk fermented with L. plantarum L3 were Thr-Pro, Val-Lys, l-creatine, pyridoxine, and muramic acid, which improved the taste and nutritional qualities of the milk. Moreover, the water-soluble peptides derived from L3 fermented milk exhibited high antioxidant properties and angiotensin I-converting enzyme inhibitory (ACEI) activities. Additionally, 152 peptides were found using liquid chromatography-mass spectrometry (LC-MS/MS). Furthermore, endogenous enzymes secreted by L. plantarum L3 cleaved β- and α-casein to release six ACEI peptides (ACEIPs), nineteen antioxidant peptides (AOPs), and five antimicrobial peptides (AMPS). Overall, these findings could be valuable in improving the quality of fermented milk.
This study identified characteristic whey proteins from Zhongdian Yak (ZY), Diqing Yellow Cattle (DYC), and Cattle Yak (CY), revealing insights into their potential functions and released peptides. A ...total of 118 whey proteins were quantified in milk obtained from the three breeds of cattle, including seven characteristic proteins (IGL@ protein, 40S ribosomal protein S9, calreticulin, etc.) in CY milk and two characteristic proteins (RNA helicase and uncharacterized protein (A0A3Q1LFQ2)) in ZY milk. These characteristic proteins are involved in the phagosome and Fc gamma R-mediated phagocytosis pathways, exhibiting immunoprotective activities, verified through molecular docking. Furthermore, the molecular docking results showed five whey proteins (IGL@ protein, rho GDP-dissociation inhibitor 1, small monomeric GTPase, action-like protein 3, and adenylyl cyclase-associated protein) interacted with TLR4 through multiple hydrogen and hydrophobic bonds. Therefore, these proteins may exert immunomodulatory functions by inhibiting TLR4. Meanwhile, whey proteins produced bioactive peptides, such as antioxidant peptides and ACE inhibitory peptides after simulated gastrointestinal digestion (SGID). The whey proteins and bioactive peptides from CY exhibited more types and activities than the ZY and DYC whey proteins. This study provides a theoretical basis for promoting formula milk powder production.
•118 whey proteins and their potential functional activities in three breeds of milk were revealed.•Nine characteristic whey proteins were identified from ZY, DYC, and CY milk.•Characteristic proteins mainly participate in phagosome and Fc gamma R-mediated phagocytosis.•Five characteristic whey proteins exert immunomodulatory function by inhibiting TLR4.•Bioactive peptides such as ACE inhibitory peptides from whey protein were released after SGID.
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•Enzymatic hydrolysis of Rushan cheese by-products yielded bioactive peptides.•Two novel peptides FDRPFL and KWEKPF with ACE inhibitory activity were identified.•FDRPFL and KWEKPF ...showed non-competitive and mixed inhibition patterns, respectively.•Interaction between the two peptides and ACE was due to hydrogen bonds and ionic bonds.•MD simulations revealed that two peptides formed stable and compact complexes with ACE.
To realize the high-value utilization of Rushan cheese by-product, Rushan cheese whey was used as a raw material to prepare angiotensin-Ⅰ-converting enzyme inhibitory peptides (ACEIPs). After enzymatic hydrolysisn and ultrafiltration, the sequences of peptides were identified by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Two novel ACE inhibitory peptides Phe-Asp-Arg-Pro-Phe-Leu (FDRPFL) and Lys-Trp-Glu-Lys-Pro-Phe (KWEKPF) were identified. Additionally, both of the peptides exhibited good water-solubility and no toxicity according to in-silico prediction. Fourier transform infrared spectroscopy results show that both FDRPFL and KWEKPF were enriched in β-turn and β-sheet structures. Lineweaver-Burk plots revealed that FDRPFL and KWEKPF exhibited non-competitive and mixed inhibition patterns, respectively. Molecular docking and MD simulation showed that hydrogen bonds and ionic bonds forces allowed FDRPFL and KWEKPF to form stable and compact complexes with ACE. In conclusion, enzymatic hydrolysis of Rushan cheese by-products yields bioactive peptides, increases the added value of whey and reduces environmental pollution.
•Moringa oleifera Lam. seeds protein was converted to peptides by Alcalase hydrolyzed.•Peptides possess health-promoting activities.•Peptides could be as promising food additives for developing new ...functional food.
Moringa oleifera (MO) seeds treated as a new resource food rich in protein (37.48%), but, little know the bioactive benefits and peptide composition of protein hydrolysates. In this study, ultrafiltrated peptide fractions of MO seed proteins hydrolysates (MOSPH) were analyzed for their antioxidant, anti-hypertension and sleep-promoting activities. LC-MS/MS was used to identify the peptide composition of the molecular weight (MW) <3 kDa fraction. The results showed that MOSPH and the lower MW peptides fraction, especially the MW <3 kDa fraction, exhibited higher free radical scavenging and reducing capacity, in vitro angiotensin I-converting enzyme (ACE) inhibitory capacity and vasodilatory and anti-hypertensive effects on spontaneously hypertensive rats (SHR) after the development of hypertension, sleep-promoting and anticonvulsant effects in male ICR mice. Furthermore, four potential bioactive peptides (pepsite score > 0.3) from MW <3 kDa fraction of MOSPH were explored via in silico approach, of which a novel dual-function peptide IWHHTFYNELR (IR-11) exhibited higher ACE inhibitory activity (IC50 = 1.057 mg/mL) and DPPH•-clearing activity (IC50 = 0.404 mg/mL). Molecular docking indicates that IR-11 interacted with ACE and DPPH• through hydrogen bonding and hydrophobic forces. Our results suggested that MO seed proteins peptides can be a potent functional agents for developing new functional food.
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