Characterization of physicochemical and immunogenic properties of allergenic proteins altered by food processing:a review

Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.

Food-derived bio-functional peptides for the management of hyperuricemia and associated mechanism

Hyperuricemia,a metabolic disorder related to uric acid metabolism dysregulation,has become a common metabolic disease worldwide,due to changes in lifestyle and dietary structure.In recent years,owing to their high activity and few adverse effects,food-derived active peptides used as functional foods against hyperuricemia have attracted increasing attention.This article aims to focus on the challenge associated with peptide-specific preparation methods development,functional components identification,action mechanism(s)clarification,and bioavailability improvement.The current review proposed recent advances in producing the food-derived peptides with high anti-hyperuricemia activity by protein source screening and matched enzymatic hydrolysis condition adjusting,increased the knowledge about strategies to search antihyperuricemia peptides with definite structure,and emphasized the necessity of combining computer-aided approaches and activity evaluations.In addition,novel action mechanism mediated by gut microbiota was discussed,providing different insights from classical mechanism.Moreover,considering that little attention was paid previously on the structure-activity relationships of anti-hyperuricemia peptides,we collected the sequences from published studies and make a preliminary summary about the structure-activity relationships,which in turn provided guides for enzymatic hydrolysis optimization and bioavailability improvement.Hopefully,this article could promote the development,application and commercialization of food-derived anti-hyperuricemia peptides in the future.

Effects of potassium lactate on sensory attributes,bacterial community succession and biogenic amines formation in Rugao ham

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 Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could 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.

Modifiers of the Effects of Vitamin D Supplementation on Cardiometabolic Risk Factors:A Systematic Review and Meta-Analysis

The inconsistent findings concerning the effects of vitamin D supplementation on cardiometabolic risk factors and the large heterogeneity in the published literature call for further research to identify sources of heterogeneity and potential effect modifiers.We performed a meta-analysis of randomized controlled trials(RCTs)published until March 2024 that reported estimates for the effects of vitamin D supplementation on cardiometabolic factors and relevant baseline covariates of RCT participants.A total of 17656 participants from 99 RCTs were analyzed,and weighted mean differences(95%confidence intervals(CI))for the intervention status were derived using random-effects modeling.Overall,compared with the placebo,vitamin D supplementation(median dose:3320 international unit(IU)·day^(-1);range 40-120000 IU·day^(-1))had favorable effects on systolic blood pressure(SBP;-2.04(95%CI,-3.50,-0.59)mmHg;1 mmHg=0.133 kPa),diastolic blood pressure(DBP;-3.00(95%CI,-3.61,-2.39)mmHg),total cholesterol(TC;-0.12(95%CI,-0.21,-0.03)mmol·L^(-1)),fasting blood glucose(FBG;-0.13(95%CI,-0.20,-0.05)mmol·L^(-1)),hemoglobin A1C(A1C;-0.09%(95%CI,-0.13%,-0.05%)),and fasting blood insulin(FBI:-7.61(95%CI,-11.93,-3.30)pmol·L^(-1)).The benefits of vitamin D were most evident in trials performed in non-Westerners,participants with baseline 25-hydroxyvitamin D(25[OH]D)lower than 15.0 ng·mL^(-1),non-obese(body mass index(BMI)<30 kg·m^(-2)),and older(age-50 years).The findings of this study underscore the need for personalized vitamin D intervention strategies that comprehensively account for individual patient characteristics(such as ethnocultural background,age,BMI,and circulating 25[OH]D level),intervention dosage,and intervention duration to optimize cardiometabolic health outcomes.

Alteration of fecal microbiome and metabolome by mung bean coat improves diet-induced non-alcoholic fatty liver disease in mice

Dysbiosis of gut microbiota and its derived metabolites has been linked to the occurrence and development of nonalcoholic fatty liver disease.Our previous study has demonstrated that mung bean coat(MBC)might be mainly responsible for the beneficial effects of whole mung bean on high fat diet(HFD)-induced metabolic disorders.To investigate whether MBC,which is rich in dietary fiber and phytochemicals,can protect against HFD-induced hepatic steatosis in mice via targeting gut microbiota and its metabolites,we conducted this study.Results showed that MBC could effectively alleviative the obese phenotype,reduce the lipid accumulation and insulin resistance,and improve the hepatic oxidative stress and inflammatory response.Furthermore,MBC significantly prevented the HFD-induced changes in the structure and composition of gut microbiota,characterized by promoting the bloom of Akkermansia,Lachnospiraceae_NK4 A136_group,and norank_f_Muribaculaceae,and along with the elevated short-chain fatty acids concentrations.Non-targeted metabolomic analysis indicated a metabolism disorder that was obviously improved by MBC via regulating sphingolipid metabolism andα-linolenic acid metabolism.These findings suggested that MBC could improve hepatic steatosis through manipulating the crosstalk between gut microbiota and its metabolites.

Rapid Quantitative Determination of Isoprene Monomer in Living Taraxacum kok-saghyz by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.

Transcriptomics reveals substance biosynthesis and transport on membranes of Listeria monocytogenes affected by antimicrobial lipopeptide brevilaterin B

Listeria monocytogenes is a worrisome food-borne pathogen threatening global food safety.Our previous study proved that lipopeptide brevilaterin B showed efficient antibacterial activity against L.monocytogenes by interacting with the cell membrane.This research further explored the antibacterial mechanism of brevilaterin B against L.monocytogenes at the sub-minimum inhibition concentration via transcriptomic analysis.Brevilaterin B induced growth inhibition rather than direct membrane lysis in L.monocytogenes at the minimum inhibitory concentration.Transcriptomic analysis showed 1779 difference expressed genes,including 895 up-regulated and 884 down-regulated genes.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated that brevilaterin B influenced multiple pathways of L.monocytogenes,including peptidoglycan biosynthesis,membrane transport(ATP-binding cassette transports,ion transport),cellular metabolism(amino acid and lipid metabolism),ATP synthesis,and activation of the stress response(quorum sensing and bacterial chemotaxis).In conclusion,brevilaterin B affects gene expression related to biosynthesis,transport and stress response pathways on the membrane of L.monocytogenes.The present work provides the first transcriptomic assessment of the antibacterial mechanism of lipopeptide brevilaterin B at the gene level.

Immunological disturbance effect of exogenous histamine towards key immune cells

Histamine in food has attracted widespread attention due to the potential toxicity and associated health risk.However,its influences on immunological components,especially the function of key immune cells,are still poorly known.In this work,we explored the effects of exogenous histamine on the function of key immune cells such as intestinal epithelial cells,dendritic cells,and T cells.The results showed that histamine could affect the expression of allergy-related genes in CMT93 cells at a high dose of histamine.Moreover,it’s found that histamine could cause an imbalance in the levels of relevant immune factors secreted by dendritic cells and T cells,especially those related to allergy.At the same time,the proportion of MHC class IIpositive dendritic cells and the proportion of T helper 2(Th2)cells in CD4^(+)T cells increased after histamine stimulation.We concluded that the presence of a certain level of histamine in food may affect the expression of allergy-related cytokines,disrupt the balance of the immune homeostasis,and potentially lead to adverse immune reactions.This work demonstrated the importance of including the estimation of histamine’s immune safety in aquatic products rather than merely considering the potential risk of food poisoning.

PMN-MDSC:A Culprit Behind Immunosenescence and Increased Susceptibility to Clostridioides difficile Infection During Aging

Susceptibility to pathogens in the elderly is heightened with age,largely because of immunosenescence.As an immune regulatory organ,bone marrow creates immune cells that move to other organs and tis-sues through the blood.Despite the significance of this process of this organ,there is limited research on changes in immune cell generation in the bone marrow and their effects on immunosenescence.In this study,the compositions of immune cells in bone marrow from young(three months)and old(24+months)mice were compared by means of mass cytometry,with further validation obtained through the reanalysis of single-cell RNA sequencing data and cell sorting via flow cytometry.The effects of differential immune cells on immunosenescence in old mice were evaluated using the Clostridium difficile(C.difficile)infection model.Our results showed that aged mice presented with a reduction in bone tra-beculae structure,which was accompanied by a notable increase in polymorphonuclear(PMN)-myeloid-derived suppressor cell(MDSC)abundance.Through bulk-seq and reverse transcription quantitative polymerase chain reaction(RT-qPCR)analysis,we identified differential genes associated with the immune response—specifically,the Th17 cell differentiation pathway.Furthermore,the increase in exported PMN-MDSCs to the large intestine resulted in increased gut permeability and inflammatory damage to the colon following C.difficile infection.After clearing the PMN-MDSCs in old mice using the anti-Gr-1 antibody,the symptoms induced by C.difficile were significantly relieved,as evidenced by an inhibited IL-17 pathway in the colon and reduced gut permeability.In conclusion,aging increases the number of PMN-MDSCs in both the generated bone marrow and the outputted intestine,which con-tributes to susceptibility to C.difficile infection.This study provides a novel target for anti-aging therapy for immunosenescence,which is beneficial for improving immune function in elders.

Oral administration of Bacillus coagulans TQ-35 alleviates allergic responses in OVA-sensitive BALB/c mice

Bacillus coagulans has been extensively studied so far,but there has been a lack of research on its usage in allergy.In this study,we designed to assess the effect of different concentrations of B.coagulans on food allergy in a BALB/c mouse model of ovalbumin(OVA)-induced food allergy and its effect on gut microbes.The assessment of symptoms,specific immunoglobulin E(IgE),T-cell differentiation,and related gene expression levels in sensitized mice by assay indicated that high doses of oral B.coagulans could alleviate allergic symptoms.Treatment with B.coagulans,in the high-dose group,significantly reduced IgE and IgG1 levels and modulated the balance of T helper type 1 cell(Th1)and Th2 and the expression of relevant genes in the spleen.16S rRNA analysis showed that probiotics improved the structure of the microbiota,in particular by boosting the percentage of Clostridia,Bacteroides vulgatus and Enterococcus faecium,and by increasing the abundance of microbial species,thereby modulating the immune system.Therefore,this study can provide insights into the practical application of B.coagulans doses to alleviate OVA allergy.

Innovative packaging materials and methods for flavor regulation of prepared aquatic products:Mechanism,classification and future prospective

Prepared aquatic products refer to ready-to-eat,heated,ready-to-cook,and paired food derived from marine products,which are growing as attractive convenience food.Flavor is a vital factor for consumers in choosing prepared aquatic products.Suitable packaging materials and methods are the crucial pathways used to maintain the flavor and control the off-flavor of prepared aquatic products.Compared to vacuum packaging and modified atmosphere packaging,innovative packaging,including biodegradable,edible,active,and intelligent packaging,has received attention due to the potential advantages of flavor regulation.The mechanism of flavor change in package-associated prepared aquatic products is surveyed in this paper according to the reaction of lipids,proteins,microorganisms,and enzymes.Further,the effects of innovative packaging materials and methods on the flavor regulation of prepared aquatic products are summarized under the investigation of typical packaging.Moreover,prospects for innovative packaging materials and methods for flavor regulation in prepared aquatic products are proposed.This review provides references and bases for developing innovative packaging that maintain the flavor and wipes off-flavor.

Determination of Natural Rubber Content in Taraxacum Kok-Saghyz by Pyrolysis Gas Chromatography-Mass Spectrometry

Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.

The effect of feed additive ethoxyquin on tilapia growth performance and potential secondary hazard to consumers

Ethoxyquin(EQ)is a widely used feed additives for aquaculture,but the potential hazard to fish and consumers are not fully understood.In this work,EQ was applied to tilapia fed with either high-fat or low-fat feed,and the changes in growth performance and intestinal barrier integrality of genetically improved farmed tilapia was observed.Additionally,the microbiota in the intestinal content and flesh was analyzed by 16S rDNA sequencing,and the flesh metabolites was measured by LC-MS/MS untargeted metabolomics.In the low-fat group,EQ increased weight gain and feed conversion rate,but reduced survival rate.In the high-fat group,only weight gain decreased,and there was no significant effect on feed conversion rate and survival rate.Additionally,the intestinal villi and microbiota diversity was impaired in both feeding conditions.Microbiota analysis revealed that EQ resulted in different composition and lower diversity of the flesh microbiota and upregulated the proportion of potential pathogens.EQ also changed the flesh metabolome,decreasing beneficial metabolites and increasing potential harmful components.This work elucidated the effect of EQ on growth performance of tilapia and implied that it has adverse effects on tilapia and may be passed on to consumers.

The synergistic effect of dietary cholesterol with fruit tannins in forming kidney stones

Prevalence of kidney stones has increased continously over several decades worldwide,the major causes of which are largely unknown.To explore the dietary causes of kidney stones,and reveal mechanisms underlying dietary risk factors inducing kidney stones,animal experiments using mice as the disease model were performed.Eight-week old male CD-1 mice were treated by ethylene glycol,cholesterol or/and apple tannins for 3 d,respectively.In the present study,the crystalline analysis in urine and kidney tissues,HE staining kidney sections as well as observation of micro-stones,tannins and cholesterol deposition in kidneys of mice in different groups were conducted.We found that gavage with ethylene glycol,cholesterol and tannins resulted in mice urine solute supersaturation in renal tubules and forming kidney stones.Significant cholesterol and tannin deposits in mouse kidney were observed by laser confocal microscopy and crystals were shown either adhered with or codeposited with cholesterol and tannin deposits.The primary crystals were found in renal cortex,medullar,especially papilla in the kidney sections under polarized microscope.These findings demonstrate that interaction of cholesterol and tannins in kidney plays a critical role in the formation of kidney stones.

Progress in the preparation,identification and biological activity of walnut peptides

Walnuts are rich in protein and are a high-quality plant protein resource.In recent years,with the growth of consumer demand for functional food and food for special medical purpose,the use of walnut protein for the preparation of functional walnut peptide ingredients or additives and other compositions has received increasing attention.However,the improvement of the yield of walnut peptides and the clarification of their functional activities are the bottlenecks that limit the development of these peptides.To this end,this article reviews the pretreatment,preparation,purification and identification processes of walnut peptides,as well as their biological activities such as antioxidant activity,antitumour activity,improvement of memory,antihypertension and regulation of metabolic disorders are elaborated to provide a reference for the industrial development of walnut peptides.

Colorimetric indicator based on zwitterionic anti-freezing hydrogel and alizarin for visual monitoring of salmon fillets freshness

Indicating hydrogels have shown the advantages of being fast, sensitive, and real-time in demonstrating the freshness of aquatic products due to their noticeable color change. In this work, an anti-freezing hydrogel embedded with pH-sensitive alizarin was developed as an original colorimetric indicator for monitoring the corruption of aquatic products at low temperatures. The anti-freezing hydrogel was prepared from 2-carboxyethyl acrylate, [2-(methacryloyloxy)ethyl]-trimethylammonium chloride, and 2-hydroxyethyl methacrylate monomers with triethylene glycol dimethacrylate as cross-linking agent. The hydrogel showed excellent anti-freezing capability, which was further incorporated with the pH-sensitive dye alizarin to gain the indicating capability. When applied in the indication of the freshness of salmon under low-temperature storage, it was found that the color changes of the indicator corresponded with the total volatile basic nitrogen contents of salmon, the correlation coefficient of which was 0.959 6. These results indicated the application potential of the hydrogels as freshness indicators during low-temperature storage or cold-chain transportation.

Contamination and Transmission of SARS-CoV-2 Variants in Cold-Chain Food and Food Packaging

INTRODUCTION The emergence of coronavirus disease 2019(COVID-19)has posed a significant threat to global health and well-being.Vaccination serves as a vital strategy in preventing and mitigating the severity of clinical symptoms.However,due to natural selection,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has evolved,resulting in various mutations(1).Currently,the World Health Organization(WHO)has identified five variants of concern,including Alpha,Beta,Gamma,Delta,and Omicron(2).Of these,only Omicron remains in circulation and has already produced nearly one thousand sub-lineages or subvariants.These mutating variants demonstrate increased infectivity and vaccine breakthrough rates,as well as more pronounced antibody escape rates(3).

Antioxidant and ACE inhibitory activities of peptides prepared from adzuki bean by semi-solid enzymatic hydrolysis

In this study,adzuki bean peptides were prepared by semi-solid enzymatic hydrolysis(SEH)and their antioxidant and Angiotensin-I-converting enzyme(ACE)inhibitory activities and internal absorption were studied.By modifying different enzymatic hydrolysis times and enzyme additions,the optimal enzymatic hydrolysis condition for SEH could be obtained as adzuki bean powder:water=4:1(w/w),alcalase:neutrase=2:1(w/w),enzyme addition 3.75%(w/w),4 h enzymatic hydrolysis at 50℃ and pH=8.Within these hydrolysis conditions,the content of adzuki bean peptides was 11.37%,the OH−scavenging rate of 1 mg/mL peptides was 72.75%,the total antioxidant capacity was 0.88±0.02 mmol/L FeSO4,the ACE inhibition rate was 77.49%.In vivo absorption test proved that the peptides prepared by SEH were absorbed faster and exhibited higher antioxidant activity compared with liquid enzymatic hydrolysis.In conclusion,the process of SEH can improve not only the efficiency of hydrolysis,but also the antioxidant and ACE inhibitory activity as well as the internal absorption of adzuki bean peptides.

Insight into the relationship between microorganism communities and flavor quality of Chinese dry-cured boneless ham with different quality grades

Microorganisms played a key role in developing the flavor quality,while few studies focused on the relationship between microbial diversity and flavor quality of dry-cured boneless ham.To explore the relationship,sensory evaluation,lipases,microorganism communities,free fatty acids and volatile compounds were investigated in dry-cured boneless ham with different quality grades(NS,WS and GS groups);the correlation between cored microbes and crucial volatiles was further evaluated by metabolic network analysis.GS group showed the highest scores in aroma and overall acceptance among three groups.The highest values of phospholipase activities(7.88 U*g−1 protein)were shown in GS group,while the lowest values of TBARS(0.93 mg/kg)were observed in GS among three groups.High-throughput sequencing revealed that fungi showed the most various among three groups;Xerochrysium,Aspergillus,Penicillium and Debaryomyces were the most genera in GS.SPME-GC-MS revealed that GS showed higher contents and numbers in volatiles than other groups;aldehydes and furans were intensely response to the variations of volatiles among these groups.Metabolic pathway further revealed that several key species derived from Penicillium and Aspergillus accelerated the formation of volatiles byβ-lipoxidation and Strecker degradation.These results indicated that molds could be the major contributors in developing and differentiating the flavor quality of Chinese dry-cured boneless ham.

Cloning,purification,and characterization of branched-chain α-keto acid decarboxylases from Lactococcus lactis strains with different 3-methylbutanal production abilities

Lactococcus lactis is an important food-grade microorganism that has been successfully applied as a starter to increase the level of 3-methylbutanal produced during the ripening of cheese.Three variants of branched-chain α-keto acid decarboxylase (KADC) were discovered in L.lactis strains with different 3-methylbutanal production abilities.Three genes encoding KADCs of varying lengths (KADC-long,KADC-middle,and KADC-short) were cloned and heterologously expressed into Escherichia coli.KADC activity was only detected in the E.coli cloned with the KADC-long-encoding gene.Homology modeling of the three KADC recombination proteins showed that an active-site residue (Glu462) and an S-pocket structure were necessary for the ability to catalyze substrates.KADC-long showed maximum activity at pH 7.0 and 30 ℃.The substrate hydrolysis and kinetic parameters demonstrated that KADC-long efficiently produces 2-methylbutanal and 3-methylbutanal.The heterologous expression of the full-length kdcA in low-3-methylbutanal-yield L.lactis strains increased their production yields.The results of this study demonstrate the function of the complete KADC in 3-methylbutanal production.