The detection and regulation advances of food allergens

Food allergy has become an important food quality and safety issue,posing a challenge to the food industry and affecting consumer health.On the one hand,from the perspective of food processing industry,the diversity of food raw material ingredients,exogenous additives,and processing forms make the presence of allergens in modern food processing more complex.In addition,due to the lack of allergen identification,effective detection and allergenicity evaluation systems,there are serious deficiencies in the current theories and techniques for food allergen screening and detection,tracking and prediction,intervention and control;On the other hand,from the perspective of public health,meeting consumers'right to know whether there are raw materials containing food allergens in processed foods,and improving the credibility of government and people's satisfaction have become urgent matters;In addition,as people come into contact with more and more new borne novel foods,the probability of food allergy is also increasing.The food safety and health problems induced by increasingly complex,widespread and severe food allergy are difficult to avoid.In view of this,in response to the increasingly serious food allergy issues,this paper introduced the detection methods of food allergens,summarized the reduction and control techniques of food allergens,and elaborated hypoallergenic foods,which aims to provide the basis for preventing and controlling food allergy and ensuring the physical health of food allergy patients.

Recent advances in the study of epitopes,allergens and immunologic cross-reactivity of edible mango

Mango(Mangifera indica L.)is a tropical fruit that is widely consumed as both fresh fruits and processed products around the world.The high incidence of mango allergy,on the other hand,has sparked widespread concern.Therefore,a summary and analysis of the current status and issues in mango allergen research can guide in-depth study on the mechanism of mango allergy and reveal effective desensitization methods.We described the incidence of fruit allergy,as well as the mechanism and clinical symptoms of mango allergy,in this review.We also looked into the structural properties of mango allergens,the effect of processing methods on mango allergens,prediction methods for mango allergen epitopes,and the current state of research on mango cross-reactive allergens and preventive measures.Finally,the research directions and ideas for the future are proposed and discussed.

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.

Allergen degradation of bee pollen by lactic acid bacteria fermentation and its alleviatory effects on allergic reactions in BALB/c mice

Food allergy as a global health problem threatens food industry.Bee pollen(BP)is a typical food with allergenic potentials,although it performs various nutritional/pharmacological functions to humans.In this study,lactic acid bacteria(LAB)were used to ferment Brassica napus BP for alleviating its allergenicity.Four novel allergens(glutaredoxin,oleosin-B2,catalase and lipase)were identified with significant decreases in LAB-fermented BP(FBP)than natural BP by proteomics.Meanwhile,metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP,indicating the degradation of LAB on allergens.Moreover,FBP showed alleviatory effects in BALB/c mice,which relieved pathological symptoms and lowered production of allergic mediators.Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity,which were closely correlated with the alleviation of allergic reactivity.These findings could contribute to the development and utilization of hypoallergenic BP products.

Validation of Molecular Detection Methods for Gluten Allergens in Infant Formula

[Objectives]To verify the specificity,sensitivity,precision and negative-positive deviation of the foodproof gluten component de-tection kit for the detection of gluten allergens in milk powder matrix,and to establish a real-time fluorescent PCR legal method for the detec-tion of gluten allergens in milk powder.[Methods]The specificity,sensitivity,precision and negative-positive deviation of the detection method of foodproof gluten component detection kit(PCR-probe method)were verified by artificially adding different concentrations of wheat bran and extracting sample DNA by kit method,and applied to sample detection.[Results] The specific detection results of two kinds of milk powder with wheat bran and buckwheat added showed that the foodproof gluten component detection kit(PCR-probe method)had good speci-ficity for wheat gluten.The results of artificially added wheat bran positive samples showed that the false positive rate and false negative rate of the kit in the milk powder matrix were O,and the sensitivity and precision were high.[Conclusions]The kit is simple to operate and has high accuracy,which is suitable for the detection of gluten allergen components in milk powder.

Changes in wheat protein digestibility and allergenicity: role of Pediococcus acidilactici XZ31 and yeast during dough fermentation

Wheat flour,as the most important source of food globally,is one of the most common causative agents of food allergy.This study aimed to investigate the effects of fermentation on wheat protein digestibility and allergenicity.Protein digestibility were evaluated using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and enzyme-linked immunosorbent assay.The effect of protein on intestinal permeability was investigated by Caco-2 cell monolayers.Co-culture fermentation with Pediococcus acidilactici XZ31 and yeast leads to improvement in digestibility of wheat protein compared to single strain fermentation.Fermentation leads to a decrease in albumin/globulin antigenicity and an increase in gluten R5 reactivity,with the most significant changes in the co-culture group.Digestion strengthen the decrease of protein antigenicity and counteracts the difference in antigenicity induced by fermentation between groups.However,pretreatment with P.acidilactici XZ31 reduces the amount of allergens across Caco-2 monolayer and attenuates the gluten-induced increase in permeability of Caco-2 cell monolayer by reducing actin polymerization and villous atrophy.Co-culture fermentation reduces gluten-induced cell monolayer damage to a greater extent than P.acidilactici XZ31 monoculture.These results gives valuable insight into the effects of P.acidilactici XZ31 fermentation on the allergenicity and toxicity of wheat proteins,which contribute to promoting the application of multi-strain leavening agent in hypoallergenic and gluten-free wheat products.

Major allergens in 8 types of allergenic foods and allergen detection techniques

In recent years,the prevalence of allergens in food warning notices,both domestically and internationally,has become the second leading concern after microbial contamination.Among the various factors that threaten human health reported by the World Health Organization,food allergy ranks fourth,and food allergy has become a global security problem.As of now,no definitive treatment for food allergies exists,making the avoidance of allergen-containing foods the most effective prevention method.Consequently,labeling foods with allergen information serves as a crucial warning for allergic populations.Moreover,to enhance comprehension of food allergies,this article provides a brief overview of their definition and sensitization mechanisms.The main focus lies in highlighting the structure of primary allergens found in eight commonly allergenic foods and the resulting clinical symptoms they cause.Additionally,a summary of commonly employed allergen detection techniques is presented,with an analysis of their principles,advantages,and limitations.Looking ahead,the integration of diverse technological approaches to establish an efficient,accurate,and affordable allergen detection method remains a significant trend.This article has certain reference value for understanding the direction of food allergies.

Enzymatic hydrolysis of silkworm pupa and its allergenicity evaluation by animal model with different immunization routes

Silkworm pupa is a nourishing food with high nutritional value,but its consumption has been greatly limited given its allergenicity.Enzyme hydrolytic technique is recognized as an effective method to reduce the allergenicity of protein.In this study,we aimed to investigate the effect of enzymolysis on the allergenicity of silkworm pupa.Crude silkworm pupa protein was extracted through alkali extraction and acid precipitation,which included 5 proteins with the molecular weights ranging from 34 kDa to 76 kDa,and silkworm pupa were then hydrolyzed by alkaline protease.The allergenicity of silkworm pupa protein and its enzymatic hydrolysates was evaluated by establishing BALB/c mice model,and the mice were immunized via intragastric gavage and intraperitoneal injection,respectively.The results indicated that the intraperitoneal inj ection immunization route induced more by detecting with antibodies,histamine and Th2-related cytokines.Moreover,mice treated with silkworm pupa protein peptide displayed no obvious allergic symptoms,indicating that enzyme hydrolytic technique could significantly reduce the allergenicity of silkworm pupa.

Structure and allergenicity of a-lactalbumin:effects of ultrasonic prior to glycation and subsequent phosphorylation

Bovineα-lactalbumin(BLA)induced severe cow's milk allergy.In this study,a novel strategy combining ultrasonication,performed before glycation,and phosphorylation was proposed to reduce BLA allergenicity.Result showed that IgE-and IgG-binding capacities and the release rates of histamine and interleukin-6 from RBL-2 H3 were reduced.Moreover,intrinsic fluorescence intensity and surface hydrophobicity were decreased,whereas glycated sites(R10,N44,K79,K108,N102 and K114)and phosphorylated sites(Y36 and S112)of BLA were increased.Minimum allergenicity was detected during BLA treatment after ultrasonic prior to glycation and subsequent phosphorylation because of considerable increase in glycated and phosphorylated sites.Therefore,the decrease in allergenicity of BLA,the effect correlated well with the shielding effect of glycated sites combined with phosphorylated sites and the conformational changes.This study provides important theoretical foundations for improving and using the ultrasonic technology combined with protein modification in allergenic protein processing.

Effect of thermal processing and fermentation with Chinese traditional starters on characteristics and allergenicity of wheat matrix

Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,and hence affect its allergenic properties.However,few reports have focused on the influence of Chinese traditional starter fermentation on wheat allergy.In this study,5 starters from different regions of China were used for fermentation,and protein characteristics were monitored by sodium dodecyl sulfate polyacrylamide gel electropheresis,and immunoreactivity analyzed by immunoassay with allergenic serum was obtained from New Zealand white rabbits.The allergenicity of steamed and baked matrices was also evaluated.The results showed that the allergenicity of wheat dough was basically increased at the beginning and then decreased during fermentation,but specific trends depend on different starters.With the progress of fermentation,especially as pH value decreased to 3.0-4.0,the allergenicity decreased significantly.Baking and steaming can reduce the allergenicity of wheat matrix,but fermentation is not a key factor affecting the allergenic activity of proteins.Our results can provide a theoretical basis for controlling wheat allergenicity in food proces sing or producing hypoallergenic food.

Ultrathin metal-organic framework nanosheets (Cu-TCPP)-based isothermal nucleic acid amplification for food allergen detection

The rapid and accurate detection of peanuts and soybeans allergen is important to the food safety. In this study, Cu-TCPP nanosheet, a kind of ultra-thin metal-organic framework(MOF)was synthesized and applied in loop-mediated isothermal amplification(named Cu-TCPP@LAMP), which can inhibit the non-specific amplification by absorbing and precise temperature releasing of single primer. As thus, Cu-TCPP@LAMP can achieve high sensitivity and specific amplification of the target gene. As a result, peanut and soybean allergens genes contained in food were successfully detected with a favorable detection sensitivity(5 ng/μL for peanuts and 10 ng/μL for soybeans)and reliable repeatability(The coefficient of variation was 3.38% for peanuts and 3.33% for soybeans). Moreover, the established method was utilized for detection of several commercial products, and had a high consistency with the standard method. Apart from food allergens, this novel assay can be widely used in other areas, such as pathogen detection, tumor nucleic acid detection and so on.

Study on mechanism of increased allergenicity induced by Ara h 3 from roasted peanut using bone marrow-derived dendritic cells

Little information was so far available about allergenic mechanism of the roasted peanut allergens during initial stages of allergy.The purpose of this study was to determine the influence of roasting(150℃,20 min)on biochemical and biological properties of Ara h 3,a major peanut allergen.Allergenicity of roasted peanut emulsion to mice,differences in uptakes between Ara h 3 purified from raw peanuts(named as Ara h 3-Raw)and that purified from roasted peanuts(named as Ara h 3-Roasted)by bone marrow-derived dendritic cells(BMDCs)and the implication of cell surface receptors involving in uptake,and changes in glycosylation and structure of Ara h 3 after roasting were analyzed in this study.This study suggested that roasting increased allergenicity of peanut to BALB/c mice.Maillard reaction and structural changes of Ara h 3 induced by roasting significantly altered the uptake of Ara h 3-Roasted by BMDCs,and modified Ara h 3 fate in processes involved in immunogenicity and hyper allergenicity,indicating that food processing pattern can change food allergenicity.

Selection of specific nanobodies against peanut allergen through unbiased immunization strategy and the developed immuno-assay

Peanut allergy is considered to be a major health issue with global effects.To date,no effective curative approach has been applied for the therapy of the anaphylaxis resulting from the peanut allergens.The accurate and effective detection methods for the surveillance of allergens in food are still the primary strategies to avoid allergic diseases.In this study,nanobodies(Nbs)derived from the Heavy-Chain only Antibodies(HCAbs)were selected against the general peanut protein extract through the unbiased strategy to facilitate the development of the sandwich ELISA for the detection and surveillance of peanut allergen contamination.The target antigen of the selected Nb was identified as peanut allergen Ara h 3,and a cross-reaction was observed with the member of Gly 1 from the Ara h 3 family.The applicability of the self-paired Nb P43 on the establishment of the immuno-assay was verified.A sandwich ELISA against peanut allergen was developed,which reached a linear range of 0.2-10.6μg/mL,and a limit of detection of 53.13 ng/mL.

Effect of lipid peroxidation on the allergenicity and functional properties of soybeanβ-conglycinin(7S)and glycinin(11S)

This study aimed to analyze the effect of lipid peroxidation on the allergenicity and functional properties of soybeanβ-conglycinin(7 S)and glycinin(11 S).Oxidation complexes were determined using the lipid peroxidation method.Functional properties were analyzed based on emulsifying and foaming properties.The potential allergenicity was evaluated by in vitro and in vivo methods.The results found that oxidation altered structures of the proteins and resulted in the formation of cross-linked protein polymers.The emulsion and foaming properties of the proteins were improved after oxidation.The IgE-binding capacity of 7 S and11 S reduced after oxidation.KU812 cell assays showed that both histamine and IL-4 release decreased after oxidation treatment.A mouse model showed that oxidation reduced the IgE,IgG,and IgG1 levels,as well as reduced histamine and mMCP-1 release in serum,which might suppress the allergic reaction.In conclusion,the lipid peroxidation treatment likely causes changes to the functional properties of soybean,decreasing the potential allergenicity of 7 S and 11 S.

Site-specific N-glycosylation characterization and allergenicity analysis of globulin-1 S allele from wheat

N-glycans in many proteins are of great concern because of their strong association with food allergies. Triticum aestivum(bread wheat), a major food crop, is known as one of the “Big Eight” allergenic groups. However, little research has been done about N-glycans in wheat glycoproteins. In this study, a soluble wheat glycoprotein was purified from wheat and further identified as globulin-1 S allele(GSA). The wheat GSA displayed significant IgE-binding activity. Moreover, one N-glycosylation site and 6 kinds of N-glycans were identified by mass spectrometry, including 3 high mannose types and 3 complex types. Furthermore, the IgE-binding activity of wheat GSA is proved to be reduced by the removal of N-glycan, thermal treatment(temperatures > 80 ℃), and strong acidic treatment(pH 3.0). These findings would provide a better understanding of the effects of N-glycosylation, thermal treatment, and acidic treatment on the molecular characteristics of GSA, and further provide new insights into the development of hypoallergenic wheat products.

An innovative method used for the identification of N-glycans on soybean allergenβ-conglycinins

β-Conglycinin is one of the major allergens existed in soybean.N-Glycans attached to theβ-conglycinin influenced the immunoreactivity and antigen presenting efficiency ofβ-conglycinin.In this study,we described a new method used to release and collect the N-glycans fromβ-conglycinin,and the N-glycans existed in linear epitopes ofβ-conglycinin were identified.Glycopeptides hydrolyzed fromβ-conglycinin were purified by cotton hydrophilic chromatography.Trifluoromethylsulfonic acid was then used to release glycans from glycopeptides,and new glycopeptides containing one single N-acety1-D-glucosamine(G1 cNAc)moiety were then utilized for mass spectrometry.Five glycosylation sites(Asn-199,Asn-455,Asn-215,Asn-489 and Asn-326)and 22 kinds of glycopeptides were identified.It is noteworthy that the peptide VVN^(#)ATSNL(where^(#)represents for the glycosylation site)was analyzed to be both glycopeptide and linear epitope.Our results provided a new method for the N-glycoform analysis of food allergens,and laid a foundation for understanding the relationship between glyco sylation and food allergy.

Palyno-Morphological Study of Allergenic Flora of Samarkand, Uzbekistan

This study set out to look into the palyno-morphological characteristics of specific allergenic species from diverse plant families in Samarkand, Uzbekistan. Six different species i.e. Betula pendula, Fraxinus pennsylvanica, Magnolia × soulangeana, Pinus brutia var. eldarica, Populus alba, Quercus robur were collected, pressed, identified, and then examined under a microscope. Under light microscope, both quantitative and qualitative characteristics of the pollen grains were recorded, including pollen type, pollen size, pollen shape (polar and equatorial view), P/E ratio, mesocolpium distance, exine thickness, colpi type, colpi length, and width. It was found that a warm spring in Uzbekistan causes an early commencement of the vegetative and dusting phases, in contrast to the climatic circumstances of the researched entities’ motherland (cold spring). Studies in aeropalinology and morphology enable the resolution of numerous environmental issues. The findings highlighted the importance of pollen morphology as an identifying aid and showed how the tested species’ palynological characteristics varied. In order to promote future phylogenetic description of the Uzbekistan flora, the current study may help us better understand the palynomorphological traits of native plants. This essay only briefly and inadequately addresses these issues. The information gathered will be used to make an atlas of allergic plants in Samarkand and an electronic warning system for the general public about the spread of pollen from the city’s allergenic plants in the future.

Interactive effect of hot air roasting processes on the sensory property,allergenicity,and oil extraction of sesame(Sesamum indicum L.)seeds

Sesame seeds are a healthy food ingredient and an oil crop for sesame oil production;however,it has recently been recognized as an essential allergenic food by FAO/WHO.This research investigated the relationship between the hot air roasting process(at 120,150,and 180℃ for 10,20,and 30 min)and several quality attributes of sesame seeds since roasting is the key process for preparing sesame seeds for both consumption and oil production.The hot air process followed the central composite design.The changes of sesame in terms of color,sensory properties(odor,texture,color,and taste),allergenicity caused by oleosins(ses i 4 and ses i 5),as well as oil extraction and quality were monitored using a colorimeter,sensory evaluation panelists,ELISA,as well as oil yield and acid value,respectively.Roasting temperature influenced the product quality more than roasting time,although the two processing parameters significantly interacted with each other(P<0.001).Sensory evaluation indicated medium roasting generated attractive flavor,order,appearance,and crispy texture.Allergenicity was high in sesame seeds after high-temperature roasting,according to IgE binding capacity test.Sesame oil extraction was favored by high-temperature roasting,which,however,adversely affected the oil quality.The optimal roasting conditions were 150.5℃ for 15 min for optimized sesame seeds quality in terms of sensory properties and allergenicity,while roasting at 158℃ for 10 min was optimal for sesame oil production.The finding will benefit the sesame seed industry.

Purification and immunoglobulin E epitopes identification of low molecular weight glutenin:an allergen in Chinese wheat

As one of the most important cereals,wheat(Triticum aestivum)has high nutritional value and is widely cultivated in China.However,wheat can cause severe allergic reactions,and a growing number of people are developing allergies to Chinese wheat.Low molecular weight glutenin(LMW-GS),an important allergen in susceptible populations,is responsible for celiac disease and wheat contacts dermatitis.In this study,LMW-GS was highly purified from Chinese wheat(Xiaoyan 6)and further identified and characterized.In addition,8 peptides were predicted efficiently by 5 immunological tools,among which 5 peptides showed significant immunoglobulin E binding abilities.Two specific epitopes were found to be in the non-conserved region of the amino acid sequence of LMW-GS,which was speculated to be the specific epitope of Chinese wheat.This systematic research of LMW-GS may provide new insights into the prevention of wheat allergy and development of hypoallergenic wheat products.

Determination of egg and milk allergen in food products by liquid chromatography-tandem mass spectrometry based on signature peptides and isotope-labeled internal standard

The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.