Food Bioscience最新文献

To solve the problem of low efficiency and purity in preparation of active peptides through enzymatic hydrolysis, the xanthine oxidase (XO) inhibitory peptides were optimized according to structure-activity relationship and a heterologous expression system for these peptides was constructed. The XO inhibitory peptide AEAWMWR (IC₅₀ = 1.76 mM), which exhibited enhanced activity, was obtained by optimizing AEAQMWR (IC₅₀ = 8.85 mM) in this research. The optimized peptide AEAWMWR exhibited approximately a 5-fold increase in activity compared to the template peptide AEAQMWR. The optimization results indicated that replacing the non-hydrophobic amino acids in the middle of the sequence with W or adding W to the C-terminal of the sequence effectively improved the activity of peptides. Additionally, to further achieve low-cost and rapid preparation of the peptides AEAQMWR and AEAWMWR, the recombinant plasmids containing fusion proteins of tandem repetitive peptides were designed and expressed in Escherichia coli. The recombinant peptides AEAQMWR (IC₅₀ = 8.19 mM) and AEAWMWR (IC₅₀ = 1.57 mM) exhibited significant activity. These results demonstrate that rational optimization and microbial synthesis of peptides can efficiently prepare bio-active peptides.

Food-derived antioxidant peptides have been shown to have beneficial effects in scavenging excess free radicals. In this study, a novel multifunctional LPxTG-motif protein LPxT-GYLEQ was synthesized, and its molecular mechanism of alleviating cognitive impairment in a D-galactose (D-gal)-induced aging mice model was also investigated. The results confirmed the antioxidant effects of the LPxT-GYLEQ protein, which could scavenge excessive reactive oxygen species (ROS) in aging mice by regulating the c-Jun N-terminal kinase (JNK)/Nuclear factor erythroid 2-related factor 2 (Nrf2)/p38/Nuclear factor-k-gene binding (NF-κB) signal pathway, reduced the accumulation of β-amyloid protein (Aβ), restored the cognitive ability of mice, improved learning and memory behavior, effectively reduced the expression of inflammatory-related factors, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and increased the expression of anti-inflammatory factor interleukin-10 (IL-10). These may be related to the fact that the protein regulates the abundance of beneficial bacteria such as intestinal Akkermansia Muciniphila (Akk). All results suggest that the synthetic LPxT-GYLEQ protein may improve cognitive impairment and be a promising candidate for an anti-aging agent.

The quest for novel, potent antimicrobial agents with low resistance potential poses a significant challenge for the advancement of the food and medical sectors. This study aimed to elucidate the antibacterial potency of antimicrobial peptides derived from koumiss in a murine model. Leveraging an antimicrobial peptide database, six peptides (MP-1 to MP-6) were meticulously predicted and screened for their antibacterial properties. These peptides were subsequently synthesized using chemical solid-phase methods and their antibacterial activities were rigorously validated. Remarkably, among the six peptides, MP-4 demonstrated a profound antibacterial effect against E. coli, achieving rapid bacterial eradication within 240 min. Flow cytometry analysis further corroborated its significant bactericidal activity. In vivo experiments conducted on mice infected with E. coli revealed that oral administration of MP-4 significantly ameliorated symptoms such as lethargy, anorexia, and weight loss. Additionally, it effectively reduced the colonic E. coli burden, attenuated inflammatory responses, and favorably modulated the intestinal microbiota composition. This study not only validates the robust antibacterial activity of the koumiss-derived antimicrobial peptide MP-4, but also underscores its potential therapeutic application in mitigating E. coli infections and promoting intestinal health.

Dipeptidyl peptidase 4 (DPP4), which breaks down glucagon-like peptide 1 (GLP-1), is closely associated with glucose metabolism, and the inhibition of this enzyme is one of the important targets for the treatment of diabetes. Traditionally cinnamon and bitter melon have been in wide use in diabetes treatment, and cinnamic acid (CIA) as its main ingredient is expected to be an ideal DPP4 inhibitor. In vitro inhibition experiments showed that CIA had the lowest IC₅₀ (33.56 ± 1.13 mM) compared to the other substances in the study, suggesting that it was more effective in inhibiting DPP4. Analyses showed that adding hydroxyl and methyl groups to CIA's aromatic ring reduced its effect on DPP4; CIA and its derivatives were inhibited in a mixed way. With the exception of ferulic acid (FA), CIA and its derivatives quenched the fluorescence of DPP4 via a static quenching mechanism. Thermodynamic parameters show that the binding of CIA (the most inhibitory compound) to DPP4 was spontaneous and driven by hydrogen bonding. Atomic force microscopy and circular dichroism spectroscopy analyses reveal that upon binding with DPP4, CIA underwent a conformational change. Molecular docking results highlight, while introducing hydroxyl and methoxy groups on the aromatic ring, the superior binding capacity of CIA diminished. The study confirms that CIA is an ideal inhibitor with the highest absolute value of binding energy (−5.8) and the lowest IC₅₀ compared to other substances. By clarifying the inhibition mechanism of DPP4,the study thus provides dietary guidance for diabetic patients.

High temperatures, particularly in summer, lead to decreased yields in the industrial application of Pseudomonas plecoglossicida for 2-keto gluconic acid (2KGA) fermentation. To address this, the alterations in the transcriptomics of P. plecoglossicida in response to high-temperature stress were examined at temperatures of 32 °C, 36 °C, and 40 °C. The analysis of differential expression revealed substantial discrepancies in the number of differentially expressed genes (DEGs) at 36 °C (357) and 40 °C (1,487), primarily affecting vital biological functions. Elevated temperatures resulted in a shift in the metabolic processing of glucose, transitioning from extracellular oxidation to intracellular phosphorylation. Notable changes were observed in metabolic pathways, including the pentose phosphate pathway and tricarboxylic acid cycle. A significant observation was the decline in the activity of genes associated with extracellular glucose oxidation, accompanied by an increase in the activity of genes involved in intracellular phosphorylation pathway. This indicates a prompt and dynamic response to high-temperature stress. The investigation revealed notable alterations in genes linked to glucose metabolism, emphasizing the strain's adaptive capabilities to endure high temperatures. The reveal of adaptations are crucial for optimizing 2KGA production in challenging industrial environments.

To better understand the bitterness effect and molecule mechanism of myosin-derived peptides activating bitter receptors, the interaction between myosin-derived peptides of dry-cured ham and bitter receptors was investigated by molecular docking and molecular dynamics simulation; the signal transduction mechanism of myosin-derived peptides was explored by HEK-293T cells using calcium imaging and transcriptomics analysis. Lower CDOCKER energy was observed during the interaction between myosin-derived peptides and hT2R1 by molecular docking compared with hT2R4, hT2R5, hT2R8, hT2R14 and hT2R16. Hydrogen bonds and hydrophobic interaction were the most important interaction forces which stabilized the interaction of hT2R1 and myosin-derived peptides. Compared with LEKEKSELK and TEELEEAKK, the RMSF values and EC₅₀ values of HVLATLGEK were lower, indicating that hT2R1 was more sensitive to HVLATLGEK stimulation. Transcriptomics and KEGG analyses showed that 767 differentially expressed genes were found and mainly involved in cAMP signaling pathway, neuroactive ligand-receptor interaction, calcium signaling pathway and MAPK signaling pathway after stimulating of HVLATLGEK. Protein-protein interaction network further demonstrated that DDIT3, FOS, FOSB, MYC, EGR1 and CCN2 were the key genes to connect the six functional clusters including ligand-receptor interaction and signal transduction.

The application of natural products for regulating skin pigmentation is increasingly being acknowledged due to their security and proven efficacy. Almond (Amygdalus communis L.) is an edible nut plant with significant nutritional value and medicinal attributes. In this research, oligosaccharide (ACO-II-1) was extracted and isolated applying gel chromatography techniques from the aqueous extract of almond kernel. Structural characterization of ACO-II-1 was conducted using ESI-MS, methylation analysis and 1D/2D-NMR. The findings indicated that ACO-II-1 was composed of fructose and glucose and the glycosidic bond predominantly featured β-D-Fruf-(1 → 2)-β-D-Fru-(1 → 6)-α-D-Glcp-(1 → 1)-α-D-Glcp. Moreover, ACO-Ⅱ-1 possessed strong antioxidant activity and notable inhibitory effect on melanogenesis in forskolin (FSK)-induced B16F10 melanoma cells. Subsequent mechanism investigation was conducted and suggested that the anti-melanogenic properties of ACO-Ⅱ-1 might be attributed to its modulation of the Mitogen-activated protein kinases (MAPKs) and β-catenin signaling pathways. These results indicated that edible plant derived ACO-II-1 might be served as promising inhibitor of hyperpigmentation with potential application in pharmaceutical and skin-care sector.

Fermentation assumes a crucial role in the flavor formation of Guangxi fermented bamboo shoots (GFBS). However, the dynamics of volatile organic compounds (VOCs) during GFBS fermentation remain poorly understood. Thus, we used HS-GC-IMS and HS-SPME-GC-MS to investigate the changes in VOCs composition during GFBS fermentation, providing clear differentiation for the fermentation stages of GFBS. We identified 96 VOCs by GC-MS and 26 VOCs by GC-IMS, among which 11 VOCs were concurrently detected by both methods. Most of these VOCs were produced during the early and mid-fermentation stages. In addition, 24 VOCs were marker VOCs of GFBS during different fermentation stages. Notably, acetic acid, nonenal, (+)-beta-cedrene, 2-pinene, 2, 6-dimethylpyrazine, and trimethylbenzene can be used as markers for the late fermentation of GFBS. These results not only illuminate the complex changes in VOCs, but also provide valuable insights for enhancing fermentation techniques to enhance the flavor quality of GFBS.

Pickering emulsion gels (PEGs) stabilized by microgel particles (MPs) have a wide range of applications. However, the extent and mechanisms of lipid digestion in these PEGs are still unclear. In this study, we explored how the concentration of β-glucans MPs and different stabilizers influence the lipid digestion profiles. Our findings revealed a significant role of β-glucans MPs in modulating lipid digestion, with a reduction in lipid digestion rate and extent correlated with an increase in MPs concentration. Notably, compared to droplets stabilized by other agents, emulsions stabilized by β-glucans MPs exhibited the lowest initial release rate (0.81 ± 0.08 FFA%/min) and final degree of digestion (18.96% ± 0.42%) of free fatty acids. Lipid droplets stabilized by β-glucan MPs were able to effectively resist the effects of high ionic strength and complex components in the oral and gastric environments, maintaining their structural integrity and preventing droplet aggregation. Our results indicated that β-glucans MPs are not only effective stabilizers but also provide a novel approach to controlling lipid digestibility.