Search

Probiotics are used in cheese fermentation to endow the product with unique functional properties, such as enhanced flavor and aroma development through proteolysis and lipolysis. In this study, two probiotic Lactobacillusstrains, Lactobacillus plantarumA3 and Lactobacillus reuteriWQY-1, were selected to develop new probiotic cheeses in the form of single- and mixed-strain starters. The results demonstrated that the L. plantarumA3 single-strain group and the L. plantarumA3/L. reuteriWQY-1 mixed fermentation group exhibited superior product performance, particularly the release of functional hydrolysates during cheese ripening. Furthermore, Label-free quantitative proteomic analysis revealed 26 unique antioxidant peptides in the L. plantarumA3 single-strain group and 53 in the L. plantarumA3/L. reuteriWQY-1 mixed fermentation group. Among these, CMENSAEPEQSLACQCL (β-lactoglobulin), CMENSAEPEQSLVCQCL (β-lactoglobulin), and IQYVLSR (κ-casein) have been found to possess potential antioxidant properties both in vitroand in vivo. This confirmed that milk-derived protein peptides in cheese products exhibit potential antioxidant functions through the hydrolysis of probiotic strains.

Hyperuricemia is a metabolic disorder caused by abnormal purine metabolism, resulting in abnormally high serum uric acid. In this study, a novel Levilactobacillus brevisPDD-5 isolated from salty vegetables was verified with the function of alleviating hyperuricemia. The relevant effects of L. brevisPDD-5 in lowering uric acid were analyzed by in vitroand in vivoexperiments. The results showed that the L. brevisPDD-5 has (68.86 ± 15.46)% of inosine uptake capacity and (95.75 ± 3.30)% of guanosine uptake capacity in vitro. Oral administration of L. brevisPDD-5 to hyperuricemia rats reduced uric acid, creatinine, and urea nitrogen in serum, as well as decreased inosine and guanosine levels in the intestinal contents of rats. Analysis of relevant markers in the kidney by ELISA kits revealed that L. brevisPDD-5 alleviated oxidative stress and inflammation. Moreover, the gene expression of uric acid transporter 1 (URAT1) and glucose transporter 9 (GLUT9) was down-regulated, and the gene expression of organic anion transporter 1 (OAT1) was up-regulated after treatment with L. brevisPDD-5. Western blot analysis showed that L. brevisPDD-5 alleviated hyperuricemia-induced kidney injury through the NLRP3 pathway. These findings suggest that L. brevisPDD-5 can lower uric acid, repair kidney damage, and also has the potential to prevent uric acid nephropathy.

Traditional antibiotics are facing a tremendous challenge due to increased antimicrobial resistance; hence, there is an urgent need to find novel antibiotic alternatives. Milk protein-derived antimicrobial peptides (AMPs) are currently attracting substantial attention considering that they showcase an extensive spectrum of antimicrobial activities, with slower development of antimicrobial resistance and safety of raw materials. This review summarizes the molecular properties, and activity mechanisms and highlights the applications and limitations of AMPs derived from milk proteins comprehensively. Also the analytical technologies, especially bioinformatics methodologies, applied in the process of screening, identification, and mechanism illustration of AMPs were underlined. This review will give some ideas for further research and broadening of the applications of milk protein-derived AMPs in the food field.

To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham, sensory attributes, physicochemical parameters, total volatile basic nitrogen (TVBN), microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels (0 %, 0.5 %, 1 %, 2 %) were investigated; the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated. With the increase of potassium lactate from 0 % to 2 %, the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed; the abundance of Staphylococcusincreased, while the content of Halomonasdecreased. LDA effect size (LEfSe) and correlations analysis showed that Staphylococcus equorumand Lactobacillus fermentumcould be the key species to improve sensory scores and decrease biogenic amines and TVBN. Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2 % potassium lactate.

The pronounced perception of off-odors poses a prevalent issue across various categories of food ingredients and processed products, significantly exerting negative effects on the overall quality, processability, and consumer acceptability of both food items and raw materials. Conventional methods such as brining, marinating, and baking, are the main approaches to remove the fishy odor. Although these methods have shown notable efficacy, there are simultaneously inherent drawbacks that ultimately diminish the processability of raw materials, encompassing alterations in the original flavor profiles, the potential generation of harmful substances, restricted application scopes, and the promotion of excessive protein/lipid oxidation. In response to these challenges, recent endeavors have sought to explore innovative deodorization techniques, including emerging physical processing approaches, the development of high-efficiency adsorbent material, biological fermentation methods, and ozone water rinsing. However, the specific mechanisms underpinning the efficacy of these deodorization techniques remain not fully elucidated. This chapter covers the composition of major odor-causing substances in food, the methodologies for their detection, the mechanisms governing their formation, and the ongoing development of deodorization techniques associated with the comparison of their advantages, disadvantages, and application mechanisms. The objective of this chapter is to furnish a theoretical framework for enhancing deodorization efficiency through fostering the development of suitable deodorization technologies in the future.

The prerequisite for the probiotic effect of lactic acid bacteria is that they could survive the acid stress environment of production and application. In this experiment, the mechanism for the effect of different metal ion pre-stress on the acid-tolerant survival of Lactobacilluswas investigated. Scanning electron microscopy, Fourier infrared spectroscopy, and flow cytometry were used to analyze the condition of bacteria after acid treatment, which revealed that different metal ion pre-stress could improve the survival ability of Lactobacillus acidophilusCICC 6074 under low acid conditions by improving cell morphology, mitigating cell membrane damage, and regulating surface protein expression. Furthermore, Tandem Mass Tags (TMT) proteomic analysis revealed that Mn2+pre-stress showed relatively more superior protective effects on acid tolerance in L. acidophilusCICC 6074 through activation of DNA replication, RNA synthesis, S-layer protein secretion, H+-ATPase enzyme activity, etc. This study will provide new ideas and a theoretical basis for the development and application of lactic acid bacteria.

Many natural angiotensin-converting enzyme inhibitory (ACEI) peptides have been widely studied and used to prevent and control hypertension. In this study, peptideomics and 3D-QSAR models combined with experimental verification were used to rapidly screen ACEI peptides in broccoli protein hydrolysates, followed by molecular docking and intracellular antihypertensive activity analysis. The results showed that two novel peptides FVLPLR and LPWYR were obtained, and their IC50values for inhibiting ACE activity in vitrowere 3.06 μM and 19.05 μM, respectively. Molecular docking results showed that FVLPLR and LPWYR bind to ACE through hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Both peptides can promote HUVEC cells to produce vasodilator factor NO. These results indicated that broccoli protein could be used as an excellent source of ACE inhibitors.

Lipid oxidation plays a key role in the formation of flavor during hot processing. The purpose of this study was to investigate the lipid oxidation, lipid molecular changes and their effects on flavor of air-dried beef at different roasting stages. The results revealed that the degree of lipid oxidation increased and the unsaturation of fatty acids decreased from 47.30% to 30.77%. A total of 48 volatile compounds were identified by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). Notably, the types and contents of volatile compounds in S3 group exceeded those in S1 and S2, showing significant differences in the degree of separation among all groups. The aroma differences among the groups were associated with aromatic compounds formed by the oxidation of lipids. Moreover, a total of 59 lipids with significant differences were identified through liquid chromatography-tandem mass spectrometry (LC-MS/MS). These lipids may have major roles in the formation of aromatic compounds, particularly triglyceride, phosphatidylcholine, and lysophosphatidylcholine. This investigation elucidated the mechanisms for the flavor developments of air-dried beef during roasting stages.

LactobacillusS-layer protein (SLP) is a biologically active protein on the cell surface. To further elucidate the structures and functions of SLP in Lactobacillus acidophilusCICC 6074, this study was conducted to identify the functional domains of SLP which is responsible for cell wall anchoring, self-assembly, and adhesion. The gene (slpA) of L. acidophilusCICC 6074 SLP was amplified by polymerase chain reaction and speculated functional domains. Fusion proteins of C-terminal truncations from SLP were exogenously expressed in Escherichia coliBL21 (DE3). FITC-labeling N-terminal truncations of SLP were synthesized. The C-terminal domain was more likely to be the binding region, and the cell wall-anchored receptor of SLP was teichoic acid. Furthermore, N-terminal truncations could self-assemble to milk fat globule membrane polar lipid liposomes observed using a fluorescence microscope. Notably, SAN1 (region 32-55) of N-terminal truncations was mainly responsible for the adhesion of SLP to HT-29 cells. These results showed that SLP played a crucial role in the functions of L. acidophilusCICC 6074, which might be of significant reference value for future studies.

To investigate the spoilage characteristics of Jinhua ham, sensory scores, volatile compounds, biogenic amine, physicochemical parameters and microbial counts were evaluated between normal and spoiled hams. The results showed that off-odors of spoiled hams were dominated by rancid, sour, sulfide and ammonia odors derived from these compounds including butanoic acid, methanethiol and dimethyl disulfide. Total content of biogenic amine in spoiled hams was significantly higher (more than 10-fold) compared with normal hams, and putrescine, cadaverine and histamine were the key components of biogenic amine of spoiled hams. Lower salt content, and higher moisture, TVB-N and thiobarbituric acid reactive substances (TBARS) values were observed in spoiled hams compared with normal hams. The populations of Enterobacteriaceae and Enterococcus of spoiled hams were obviously higher than that of normal hams. High moisture and low salt content caused the abnormal growth of Enterobacteriaceae and Enterococcusin spoiled hams, which contributed to the spoilage of Jinhua ham.

Hydrogels obtained from natural polymers have received widespread attention for their excellent biocompatible property, nontoxicity, easy gelation, and functionalization. Polysaccharides can regulate the gut microbiota and improve the intestinal microenvironment, thus exerting the healthy effect of intestinal immunity. In an active substance delivery system, the extent and speed of the substance reaching its target are highly dependent on the carrier. Thus, the smart active substance delivery systems are gradually increasing. The smart polysaccharide-hydrogels possess the ability in response to external stimuli through changing their volume phase and structure, which are applied in various fields. Natural polysaccharide-based hydrogels possess excellent characteristics of environmental friendliness, good biocompatibility, and abundant sources. According to the response type, natural polysaccharide-based hydrogels are usually divided into stimulus-responsive hydrogels, including internal response (pH, temperature, enzyme, redox) and external response (light, electricity, magnetism) hydrogels. The delivery system based on polysaccharides can exert their effects in the gastrointestinal tract. At the same time, polysaccharides may also take part in regulating the brain signals through the microbiota-gut-brain axis. Therefore, natural polysaccharide-hydrogels are considered as promising biomaterials, which can be designed as delivery systems for regulating the gut-brain axis. This article reviews the research advance of stimulus-responsive hydrogels, which focus on the types, response characteristics, and applications for polysaccharide-based smart hydrogels as delivery systems.

Ulcerative colitis (UC) is a recurrent gastrointestinal infection within the spectrum of inflammatory bowel disease, posing risks associated with long-term medication. Consequently, this study aimed to investigate the effects of novel duck liver protein-derived bioactive peptides, characterized by a higher safety profile, on dextran sulfate sodium (DSS)-induced colitis in mice. The results indicated that the retention rate of VIESPPEI remained above 80% following simulated gastrointestinal digestion in vitro, demonstrating strong stability and practical application potential. The peptide VIESPPEI was found to alleviate weight loss in colitis-afflicted mice, inhibit the elevation of the disease activity index (DAI), and significantly improve symptoms such as atrophy and shortening of the colon. Histological examination further confirmed that VIESPPEI intake promoted the recovery of acute colitis in mice. Additionally, it significantly reduced myeloperoxidase activity and increased superoxide dismutase and catalase activities in the colon tissues of UC mice. Notably, a substantial increase in beneficial gut microbiota and the populations of three beneficial bacteria species (Anaplasmaspp., Tannabacteriumspp., and Bifidobacteriumspp.) that produce short-chain fatty acids, along with a decrease in pathogenic groups such as Streptococcusand Turicibacter, may account for the improvement in colitis observed in UC mice treated with VIESPPEI. This study provides new evidence that VIESPPEI alleviates UC and provides a theoretical basis for the development of functional peptide beverages.

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.

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 EC50values 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.

Nitrite (NIT) can be degraded by lactic acid bacteria (LAB) via three pathways, including reduction by nitrite reductase (NiR), acid, and certain metabolites, where enzymatic degradation is the dominant form. This review discusses the classification, structure, and related genes of NiR, as well as the process of NIT degradation, the influencing factors, and the main applications in food and the environment. NiRs are classified into four categories, namely, copper-type reductases (CuNiRs), cytochrome cd1-type reductases (cd1NiRs), iron redox-dependent reductases (FdNiRs), and polyhemoglobin creductases (ccNiRs). NIT via the nirK/nirSgenes encoding CuNiRs/cd1NiRs reduces residual NIT from natural and anthropogenic activities to nitric oxide (NO). CuNiRs and cd1NiRs can accept extracellular NO3−and bind to the enzyme-activated intracellular receptor proteins for further degradation to NO2−are affected by various internal and external factors, such as structural sites and pH. NiR generated from LAB has extensive applications mainly in the food industry and environment, which will be beneficial to promote low-nitrification life and maintain the ecological environment, having a good application prospect.

Diabetes is a major metabolic disease that requires long-term pharmacotherapy. Bioactive peptides have unique advantages such as higher potency, selectivity, and safety over small molecules and have achieved great success in the treatment of diabetes. We previously isolated a dipeptidyl peptidase-IV (DPP-IV) inhibitory peptide VPLVM with IC50= 99.68 μM from the protein hydrolysates of broccoli stems and leaves. Here, we evaluated the interaction with DPP-IV, transport, stability, and in vivo hypoglycemic effects of VPLVM. VPLVM interacted closely and steadily with DPP-IV at S1 and S2 pockets. VPLVM had a good gastrointestinal enzyme resistance and was transported through the Caco-2 cell monolayer via paracellular diffusion and by the PepT1 with a Pappof 6.96 × 10–7cm/s. VPLVM has a t1/2of 12.56 ± 0.41 min in vitro plasma stability. In the oral glucose tolerance test, VPLVM showed an excellent hypoglycemic effect at 30 min after administration. VPLVM has potential as a candidate for the treatment of hyperglycemia.

Lactobacillus plantarumA3 strains from Sichuan pickle has good fermentation characters during the texture and flavor formation of yoghurt. Sensory profiling and amino acid evaluation proved the novel taste of L. plantarumfermented yoghurt were significant different with the former plain yoghurt.

Soy isoflavone glycoside cannot be effectively absorbed by the human intestinal tract, but probiotics with related hydrolases can transform it into aglycone to promote its absorption. In this study, a novel flavonoid-enriched yogurt was developed using an isolated β-glucosidase-producing strain (Lactiplantibacillus plantarumGY). The flavonoid aglycone-enhanced yogurt was fed to ICR mice for 21 days, and its effects were observed. The yogurt can affect the gut microbial diversity of mice, especially increasing the abundance of Parasutterella, the BacteroidalesS24-7 group, and Phascolarctobacteriumin the intestinal tract of mice. Meanwhile, the ratio of Bacteroidetes/Firmicutes in the intestinal tract of mice fed with the flavonoid aglycone-enriched yogurt increased. The difference in the content of butyric acid between the L-GY + IS and the control groups was significant (P< 0.05). Therefore, milk fermentation with β-glucosidase-producing strains is a promising approach for developing flavonoid glycoside-enriched yogurt products.

The purpose of this study is to develop a new type of nanodrug delivery material by modifying milk polar lipid (MPL) liposomes with the S-layer protein. LIP-RLSFNP (MPL liposomes encapsulating RLSFNP (Arg–Leu–Ser–Phe–Asn–Pro)) and SLP-LIP-RLSFNP (S-layer protein-modified LIP-RLSFNP) were prepared and characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, confocal laser scanning microscopy, surface plasmon resonance, and mastersizer dynamic light scattering measurements. The results showed that the S-layer protein could modify the surface of MPL liposomes, stabilize the shape of the vesicles, and improve the resistance to external interference. Furthermore, SLP-LIP-RLSFNP showed better performance in in vitroand in vivoexperiments compared with LIP-RLSFNP in terms of promoting absorption and delayed release. The findings suggested that MPL liposomes modified with the S-layer protein have potential for use as an effective delivery system for therapeutic proteins and peptides.

The ability to survive in the harsh gastrointestinal tract (GIT) environment is essential for Lactobacillus reuteri(L. reuteri) exhibiting beneficial effects. In this study, we found that the hydrophobicity and auto-aggregation of L. reuteriSH23 were significantly decreased and biofilm production was also significantly decreased when L. reuteriSH23 passes through the simulated GIT. Furthermore, according to the comparative transcriptome analysis, gene expression involved in the cell envelope, metabolic processes, common stress response, regulatory systems, and transporters were also affected. Meanwhile, label-free quantitative proteomics was used to identify the differential expression of surface proteins of L. reuteriin response to simulated gastrointestinal fluid. Proteins related to the ABC transporters (Lreu_0517, Lreu_0098, and Lreu_0296) and LPxTG anchor domain proteins were upregulated in the cell surface after gastrointestinal fluid treatment, which is useful for adherence and colonization of L. reuteriin the GIT. Additionally, the recombinant Mub protein could also enhance the survival ability of L. reuteriSH23 in GIT stress environment. This study provides a comprehensive understanding of the adaptation and adhesion mechanisms of L. reuteriSH23 under the gastrointestinal tract by the transcriptomics and proteomics analysis, and mucus-binding proteins were involved in the adhesion and GIT tolerance process.

Sugar-smoking contributes to improving flavor attributes of meat products. However, there is rather limited information concerning the relationship between sugar-smoking process parameters and volatile compound (VC) fingerprinting as well as related quality attributes of sugar-smoked chicken. In this work, the changes in VC across the whole sugar-smoking process were determined and analyzed and physicochemical properties, free fatty acid, thiobarbituric acid reactive substances values, and E-nose were also performed to characterize the quality properties of sugar-smoked chicken breast (CB) and chicken skin (CS). Results suggested that a higher amount (P < 0.05) of total VC was observed in CS compared with CB during the whole processing, which may be correlated with higher thiobarbituric acid reactive substances values, and higher polyunsaturated fatty acid/saturated fatty acid ratio. According to E-nose analysis, the volatile flavor is clearly separated in the sugar-smoking stage. Volatile fingerprinting results revealed that heterocycles were the characteristic flavor formed during sugar-smoking process and hexanal, nonanal, furfural, 5-methyl-2-furancarboxaldehyde, and 2-acetyl-5-methylfuran were the major volatiles of the CS, which was closely related to lipid oxidation and caramelization reaction. Above all, the flavor of sugar-smoked chicken was mainly derived from CS and sugar-smoked process improved the flavor of CS. This study could provide theoretical guidance for regulation of the color and flavor of sugar-smoked chicken and further promote the development of the industry.

In this study, fermentation with Lactobacillus plantarumand Saccharomyces cerevisiaewas applied to improve the flavor of cured duck leg meat. Odor and taste evaluations, lipid oxidation, volatile flavor substances, and protein degradation were determined to investigate the effects of microbial fermentation on flavor improvement. The results showed that the utilization of L. plantarumrepresented the most significant effect on lipid peroxidation inhibition (the lowest value of thiobarbituric acid reactive substances and the highest content of polyunsaturated fatty acids) and also enhanced the generation of volatile flavor substances than nonfermented duck meat. Microbial fermentation accelerated protein degradation in duck meat. S. cerevisiaecould produce glutamate to promote the umami taste flavor of cured duck leg meat, and L. plantarumsignificantly improved the sweet taste by releasing alanine. Meanwhile, mixed fermentation with the two microbial species resulted in the combination of both of their advantages. These findings not only indicate the potential application of microbial fermentation in characteristic duck meat but also indicate that fermentation improves sensory properties of duck products significantly.

Umami peptides can help reduce the salt content in foods while still maintaining a savory taste. Few studies have reported the bioactivity of umami peptides after consumption. We studied the bioactivities of 12 umami peptides after gastrointestinal digestion. Three umami peptides exhibited angiotensin I-converting enzyme (ACE) inhibitory and antioxidant activity after digestion. Six novel peptides were identified from digestion solutions of the peptides by HPLC-MS/MS. Among them, CC, CCNK, and HCHT had both ACE inhibitory activity (IC50values were 9.81, 9.00, and 114.99 μM, respectively) and antioxidant activity (strong 1,1-Diphenyl-2-pycryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging activities). AHSVRF had strong ACE inhibitory activity. These peptides increased the nitric oxide concentration and decreased the content of endothelin-1 in a medium of human umbilical vein endothelial cells in a dose-dependent manner. Experiments with damaged HepG2 cells showed that peptides CC, CCNK, and HCHT had antioxidant activity through their cytoprotective effects and by reducing the reactive oxygen species content. The results indicated that umami peptides may provide many health benefits after consumption.

Neonatal necrotizing enterocolitis (NEC) is a common and devastating disease. The objective of this research was to investigate the protective mechanisms of milk polar lipids (MPLs) on the attenuation of lipopolysaccharides (LPS)-induced intestinal inflammation and apoptosis. MPLs were extracted from buttermilk and analyzed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A neonatal NEC rat model was used to investigate the effects of MPLs on NEC and its underlying mechanisms. Hematoxylin–eosin (H&E) staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay were used to observe intestinal morphological changes and intestinal epithelial cell apoptosis, which showed that MPLs could reduce NEC symptoms and intestinal apoptosis. The expressions of IL-6, IL-8, and TNF-α in the MPL group was significantly downregulated (P< 0.05), and the expression levels of IL-10 were significantly upregulated (P< 0.05). At the same time, MPLs also significantly reduced (P< 0.05) activation of the LPS-induced TLR4/NF-κB signaling pathway. Furthermore, MPLs inhibit apoptosis by reducing the expressions of Bax, caspase-9, and caspase-3 and by increasing the expression of Bcl-2. In conclusion, MPLs could reduce NEC symptoms in mice by inhibiting cell inflammation and protecting against intestinal apoptosis.

Aim:Confirmation of the enzymatic activity of Class A sortase (SrtA) in probiotic strain Lactobacillus acidophilusassociated with the adhesion properties. Materials & methods:SrtA from L. acidophilusATCC 4356 was purified and its enzymatic properties was investigated by site-directed mutagenesis approach and the sensitivity to metal ions was also detected. Results:SrtA of L. acidophilusATCC4356 can recognize LPxTG and LPxTD sorting motifs. The active sites of SrtA include His137, Cys198 and Arg205. Furthermore, acacetin can increase the activity of SrtA, while phenyl vinyl sulfone could effectively inhibit the activity of SrtA with an IC50of 143.32 μg/ml. The adhesion ability of L. acidophiluswas also decreased resulting from the inhibition of SrtA activity. Conclusion:The unique properties of SrtA of L. acidophiluscan provide some insights into the development of high-adhesion Lactobacillusstrains in the GI tract.

The objective of this research was to investigate the effects of Lactobacillus acidophilusCICC 6074 S-layer protein on the viability, adhesion, cell cycle, and apoptosis of human colon cancer HT-29 cells and to explore their molecular mechanism of tumor suppression. The S-layer protein at doses of 0, 25, 50, and 100 mg/L significantly suppressed the proliferation of HT-29 cells. The S-layer protein exerts its cytotoxic activities against colon cancer HT-29 cells by arresting the cell cycle in the G1 phase through upregulating the expression of p53, p21, and p16 and downregulating the expression of CDK1 (cyclin-dependent kinases) and cyclin B. Morphological changes were further observed by transmission electron microscopy, and the cells treated with the S-layer protein showed obvious characteristic changes of apoptosis including chromatin condensation, nuclear fragmentation, vacuoles, and so on. Furthermore, our mechanism studies indicated that the S-layer protein may induce HT-29 cell apoptosis through the death receptor apoptotic pathway and mitochondrial pathway and impede cell invasion by inhibiting the synthesis of the PI3K/AKT pathway and FasL. These results demonstrated that the L. acidophilusCICC 6074 S-layer protein may be a potential anticarcinogenic agent.

Different species and processing methods have different impacts on the flavor quality of dried Lentinus edodes. To investigate the effect of species (four species of Qingyuan: 241-4, Qingke 20, Qingke 212, and Qingke 135) and drying method (slow charcoal roasting and natural drying) on dried L. edodes, the present study quantitatively analyzed the volatile compounds, particularly lenthionine, 1-octen-3-ol, and cyclic sulfur compounds, and compared 10 L. edodesvarieties using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). A total of 136 volatiles from the 10 L. edodesvarieties were quantitatively identified. 1-Octen-3-ol, lenthionine, and associated dispersion products, including dimethyl disulfide, dimethyl trithioether, and dimethyl tetrathioether, were selected as L. edodesflavor indexes. In addition, the electronic tongue results were consistent with the results of the sensory evaluation. The flavor quality of the dried L. edodescould be objectively evaluated by GC–MS and the electronic tongue for 1-octen-3-ol and lenthionine, their dispersion products, and the umami taste. The results showed that the flavor quality of L. edodesafter a long period of charcoal roasting was improved. Although the quantity of volatile substances was reduced during charcoal roasting, the variety of volatiles was increased and the umami was improved.

Jinhua ham is a popular traditional dry-cured meat product in China and South-east Asia and highly susceptible to quality deterioration during storage. Coating incorporated with black pepper essential oil was applied to suppress lipid deterioration and improve the aroma quality of Jinhua hams. Four treatments of without coating (CK), base formula coating (BC), BC + low concentration BPEO (0.05%) (LCBPEO) and BC + high concentration BPEO (0.1%) (HCBPEO) were used for the coating of hams. The samples were analyzed for lipolysis, lipid oxidation, volatile compounds and aroma sensory after 4 months of storage at room temperature. Results showed that HCBPEO decreased (p< 0.05) thiobarbituric acid reactive substances (17.39–52.17%), LCBPEO and HCBPEO decreased (p< 0.05) lipolytic enzymes (23.94–603.57%) and lipoxygenase activities (25.58–94.29%), volatile compounds derived from lipid oxidation (47.01–115.10%), while increased (p< 0.05) contents of polyunsaturated fatty acids (18.26–43.59%) and total fatty acids (5.43–7.43%), compared with CK and BC during storage. LCBPEO and HCBPEO have higher scores (p< 0.05) of the overall aroma compared to CK and BC; We concluded that LCBPEO and HCBPEO treatments have potential to suppress lipid deterioration and improve the score of the overall aroma of dry-cured meat products during storage.

Food-derived cholesterol-lowering peptides have the practical benefit of inhibiting lipid absorption and regulating systemic cholesterol homeostasis. This work aimed to explore the antihyperlipidemia function of milk casein-derived peptides Leu-Gln-Pro-Glu (LQPE), Val-Leu-Pro-Val-Pro-Gln (VLPVPQ), and Val-Ala-Pro-Phe-Pro-Glu (VAPFPE) and investigated whether the function of these peptides affected the gut microbiome. According to the experimental findings, lipid metabolism disorder in hyperlipidemic mice was improved to various degrees by all three peptides, which dramatically lowered the levels of low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) in the serum and inhibited the buildup of lipids in the liver and the development of steatosis. VAPFPE was found to reduce intestinal cholesterol absorption and the formation of cholesterol esters by inhibiting hepatocyte nuclear factor 4α (HNF4α), niemann-pick C1-like 1 (NPC1L1), and acetyl coenzyme A acetyltransferase 2 (ACAT2) expression and increase intestinal cholesterol efflux through up-regulation of ATP-binding cassette transporter G8 (ABCG8). VAPFPE also maintained cholesterol homeostasis by up-regulating liver low-density lipoprotein receptor (LDL-R) expression. The 16S rRNA analysis revealed that all three peptides improve the gut microbial composition, and VAPFPE specifically encouraged a rise in the proportional abundance of Bifidobacterium. The results shed light on the potential applications of bioactive peptides as functional health foods for lowering cholesterol.

Tolerance to bile stress is a crucial property for lactic acid bacteria (LAB) to survive in the gastrointestinal tract and exert their beneficial effects. Whey powder enriched with milk fat globule membrane proteins (M-WPI) as a functional component is protective for strains under stress conditions. The current study investigated the key mechanisms of action involved in Lactobacillus plantarum(L. plantarum) CGMCC 23701 survival in the presence of bile and the protective mechanism of M-WPI. According to proteomic analysis (proteomics), there could be several reasons for the greater protective effect of M-WPI. These include promoting the synthesis of fatty acids and peptidoglycans to repair the structure of the cell surface, regulating the metabolism of carbohydrates and amino acids to release energy and produce a range of precursors, enabling the expression of the repair system to repair damaged DNA, and promoting the expression of proteins associated with the multidrug efflux pump, which facilitates the exocytosis of intracellular bile salts. This study helps us to better understand the changes in proteome of L. plantarumCGMCC 23701 under bile salt stress and M-WPI protection, which will provide a new method for the protection and development of functional LAB.