Lactobacillus paracasei AH2 isolated from Chinese sourdough alleviated gluten-induced food allergy through modulating gut microbiota and promoting short-chain fatty acid accumulation in a BALB/c mouse model.

BACKGROUND: A large number of people worldwide suffer from gluten-induced food allergy. As investigated in our previous research, Lactobacillus paracasei AH2 isolated from traditionally homemade sourdough in Anhui province of China showed the potential to reduce the immune reactivity of wheat protein by in vitro evaluation. However, whether L. paracasei AH2 has a role in alleviating wheat allergy in an in vivo model and its underlying mechanisms have not been elucidated. RESULTS: In this study, the alleviative effects of L. paracasei AH2 on gluten-induced allergic response were evaluated. Compared with a gluten-allergic mouse, L. paracasei AH2 suppressed anaphylaxis symptoms, gluten-specific immunoglobulin E, histamine and interleukin-4. Moreover, L. paracasei AH2 attenuated splenomegaly and induced Th1 or Treg cell differentiation to modulate the Th1/Th2 immune balance toward Th1 polarization. Short-chain fatty acid (SCFA) levels were enhanced after L. paracasei AH2 supplementation, contributing to allergy relief as well as reducing the pH of colonic contents. The α and ß diversities of the gut microbiota were modulated by L. paracasei AH2 with increased relative abundance of Lacticaseibacillus and SCFA producers (Faecalibaculum, Alloprevotella and Bacteroides genera), as well as decreased unfavorable Lachnospiraceae_NK4A136_group and Alistipes. Additionally, L. paracasei AH2 protected the intestinal barrier function by upregulating tight junctions and improved the antioxidant activities in serum. CONCLUSION: Our findings indicate that L. paracasei AH2 could act as a potential probiotic for relieving wheat allergy by modulating the gut microbiota and elevating SCFA levels. © 2023 Society of Chemical Industry.

IgE-Mediated food allergy: Current diagnostic modalities and novel biomarkers with robust potential.

Food allergy (FA) is a serious public health issue afflicting millions of people globally, with an estimated prevalence ranging from 1-10%. Management of FA is challenging due to overly restrictive diets and the lack of diagnostic approaches with high accuracy and prediction. Although measurement of serum-specific antibodies combined with patient medical history and skin prick test is a useful diagnostic tool, it is still an imprecise predictor of clinical reactivity with a high false-positive rate. The double-blind placebo-controlled food challenge represents the gold standard for FA diagnosis; however, it requires large healthcare and involves the risk of acute onset of allergic reactions. Improvement in our understanding of the molecular mechanism underlying allergic disease pathology, development of omics-based methods, and advances in bioinformatics have boosted the generation of a number of robust diagnostic biomarkers of FA. In this review, we discuss how traditional diagnostic modalities guide appropriate diagnosis and management of FA in clinical practice, as well as uncover the potential of the latest biomarkers for the diagnosis, monitoring, and prediction of FA. We also raise perspectives for precise and targeted medical intervention to fill the gap in the diagnosis of FA.

Natural immunomodulating substances used for alleviating food allergy.

Food allergy is a serious health problem affecting more than 10% of the human population worldwide. Medical treatments for food allergy remain limited because immune therapy is risky and costly, and anti-allergic drugs have many harmful side effects and can cause drug dependence. In this paper, we review natural bioactive substances capable of alleviating food allergy. The sources of the anti-allergic substances reviewed include plants, animals, and microbes, and the types of substances include polysaccharides, oligosaccharides, polyphenols, phycocyanin, polyunsaturated fatty acids, flavonoids, terpenoids, quinones, alkaloids, phenylpropanoids, and probiotics. We describe five mechanisms involved in anti-allergic activities, including binding with epitopes located in allergens, affecting the gut microbiota, influencing intestinal epithelial cells, altering antigen presentation and T cell differentiation, and inhibiting the degranulation of effector cells. In the discussion, we present the limitations of existing researches as well as promising advances in the development of anti-allergic foods and/or immunomodulating food ingredients that can effectively prevent or alleviate food allergy. This review provides a reference for further research on anti-allergic materials and their hyposensitizing mechanisms.

Food preferences, personality and parental rearing styles: analysis of factors influencing health of left-behind children.

PURPOSE: To understand the health status and problems of left-behind children (LBC) in rural China, those whose parents have moved to urban areas without them, and to focus on ways to improve their physical and mental health. METHODS: The study examined 827 children between 7 and 15 years old, selected using stratified cluster random sampling from five towns in Xiji County of the Ningxia Hui Autonomous Region. Each child was classified as either LBC or non-LBC. Measures included age- and sex-specific height and body mass index (kg/m2), a food preference questionnaire, the Revised Junior Eysenck Personality Questionnaire, and the Egna Minnen av Barndoms Uppfostran-My Memories of Upbringing (EMBU). RESULTS: Malnutrition rates for LBC and non-LBC were 14.83 % (70/472) and 7.04 % (25/355) (χ 2  = 11.86, p < 0.01). More LBC reported hating vegetables and fruits. Eysenck Personality Questionnaire profiles of LBC revealed a significantly higher degree of neuroticism and psychoticism, and a significantly lower lie scale score (p < 0.01). LBC's EMBU profiles showed that the paternal approach lacked emotional warmth and understanding and the maternal approach was characterized by favoritism, over-interference and overprotection. There were a significant negative correlation between the personality characteristic of neuroticism and liking vegetables and fruits (p < 0.01), and a negative correlation between psychoticism and liking vegetables (p < 0.05). CONCLUSION: The health status of LBC is problematic. Food preferences, personality type and parenting styles should be taken into account when measures are developed to improve the health of these children.

Mechanism of carbohydrate and protein conversion during sourdough fermentation: An analysis based on representative Chinese sourdough microbiota.

Sourdough fermentation is attracting growing attention because of its positive effects on properties of leavened baked good. However, the changes in dough features and the mechanisms behind them are not well understood, which limits its widespread use. In this study, we assessed the effects of representative lactic acid bacteria in sourdough monoculture or co-culture with yeasts on dough characteristics. Physicochemical analysis identified increased proteolysis and enhanced nutritional properties of co-culture groups. However, a reduction in organic acids contents of co-culture groups compared to monoculture was detected, and this effect was not limited by the yeast species. The RNA sequencing further demonstrated that the presence of yeast enhanced the protein metabolic activity of lactic acid bacteria, while decreased its organic acid biosynthetic activity. Moreover, the proteomic analysis revealed that endogenous metabolic proteins of flour, such as pyruvate kinase, glucosyltransferase and pyruvate dehydrogenase play a key role in carbohydrate metabolism during fermentation. This study uncovered the influence of typical microorganisms and endogenous enzymes on dough characteristics based on different aspects. Bacteria-mediated consumption of proteins and increased proteolysis in co-culture groups may underlie the improved digestibility and nutritional effects of sourdough fermented products, which provides an important basis for nutrient fortified bread making with multi-strain leavening agent.

Complexation temperature regulated the structure and digestibility of pea starch-gallic acid complexes during high pressure homogenization.

Formation of starch-polyphenol complexes by high pressure homogenization (HPH) is widely used to reduce starch digestibility and delay the postprandial glycemic response, thereby benefiting obesity and associated metabolic diseases. This study investigated the effect of complexation temperature on multi-scale structures, physicochemical and digestive properties of pea starch-gallic acid (PS-GA) complexes during HPH process, while also elucidating the corresponding molecular mechanism regulating in vitro digestibility. The results demonstrated that elevating complexation temperature from 30 °C to 100 °C promoted the interaction between PS and GA and reached a peak complex index of 9.22 % at 90 °C through non-covalent binding. The enhanced interaction led to the formation of ordered multi-scale structures within PS-GA complexes, characterized by larger particles that exhibited greater thermal stability and elastic properties. Consequently, the PS-GA complexes exhibited substantially reduced digestion rates with the content of resistant starch increased from 28.50 % to 38.26 %. The potential molecular mechanism underlying how complexation temperature regulated digestibility of PS-GA complexes might be attributed to the synergistic effect of the physical barriers from newly ordered structure and inhibitory effect of GA against digestive enzymes. Overall, our findings contribute to the advancement of current knowledge regarding starch-polyphenol interactions and promote the development of functional starches with low postprandial glycemic responses.

Allergenicity Modulation of Casein with the Modifications of Linearization, Cross-Linking, and Glycation via the Regulation of Th1/Th2 Homeostasis.

Casein (CN) is the primary allergenic protein in cow's milk, contributing to the worldwide escalating prevalence of food allergies. However, there remains limited knowledge regarding the effect of structural modifications on CN allergenicity. Herein, we prepared three modified CNs (mCN), including sodium dodecyl sulfate and dithiothreitol-induced linear CN (LCN), transglutaminase-cross-linked CN (TCN), and glucose-glycated CN (GCN). The electrophoresis results indicated widespread protein aggregation among mCN, causing variations in their molecular weights. The unique internal and external structural characteristics of mCN were substantiated by disparities in surface microstructure, alterations in the secondary structure, variations in free amino acid contents, and modifications in functional molecular groups. Despite the lower digestibility of TCN and GCN compared to LCN, they significantly suppressed IL-8 production in Caco-2 cells without significantly promoting their proliferation. Moreover, GCN showed the weakest capacity to induce LAD2 cell degranulation. Despite the therapeutic effect of TCN, GCN-treated mice displayed the most prominent attenuation of allergic reactions and a remarkably restored Th1/Th2 imbalance, while LCN administration resulted in severe allergic phenotypes and endotypes in both cellular and murine models. This study highlighted the detrimental effect of linear modifications and underscored the significance of glycation in relation to CN allergenicity.

Effects of hazelnut protein isolate-induced food allergy on the gut microenvironment in a BALB/c mouse model.

Hazelnuts are reported as among the nuts that cause severe allergic reactions. However, few systematic studies exist on the changes in the gut microenvironment following hazelnut allergy. This study focused on the effects of hazelnut allergy on the duodenum, jejunum, ileum and colon microenvironment in vivo. We established a hazelnut protein isolate (HPI)-allergic mouse model, which was distinguished by the visible allergy symptoms, dropped temperatures and enhanced allergic inflammatory factor levels in serum, such as HPI-specific immunoglobulin E (sIgE), sIgG2a, interleukin-4, histamine, mouse mast cell protease-1, TNF-α, monocyte chemotactic protein-1 and lipopolysaccharide. For HPI sensitized mice, aggravated mast cell degranulation, severe morphologic damage and inflammatory cell infiltration were observed in the duodenum, jejunum, ileum, and colon, while goblet cell numbers were reduced in the duodenum, jejunum and ileum. Secretory IgA of the jejunum and tight junctions of the duodenum and jejunum were decreased significantly after HPI sensitization. There was no remarkable difference in the pH values of small intestinal contents, but the pH values of colonic contents were elevated, which was due to the decreased short-chain fatty acids (mainly acetate, propionate and butyrate) in the colon. The antioxidant capacity of both large and small intestinal contents declined after HPI sensitization, as evidenced by the increased malondialdehyde and decreased superoxide dismutase activity. HPI sensitization induced gut microbiota dysbiosis with decreased α diversity and altered ß diversity in colonic contents. Spearman correlation analysis indicated that the increased characteristic genera, namely Bacteroides, Lactobacillus, Alloprevotella, Erysipelatoclostridium, Parabacteroides, and Helicobacter, played potentially synergistic roles in promoting allergy and gut microenvironment dysregulation.

Combination of Gut Microbial Features and the Proteomic Pattern Revealed Changes in Specific Intestinal Luminal Factors and Mechanisms of Their Regulation of Gluten Allergy.

Recent research consensus has highlighted the role of intestinal luminal factors in the association between intestinal microenvironment homeostasis and food allergy. However, the association between intestinal immune homeostasis and food allergy-related proteomic features remains elusive. In this study, we aimed to investigate the changes in gluten allergy (GA)-defined phenotypes and endotypes and intestinal microenvironment factors in BALB/c mice and linked GA to colonic proteomic signatures. Combined with increased allergy and diarrhea scores, intense antibody responses and abnormalities in T-cell cytokine production were induced in mice. GA-associated disruption of intestinal microenvironment homeostasis was underlined by the increased colonic pH, decreased intestinal antioxidant capacity, impaired intestinal barrier function, and decreased production and imbalanced proportions of short-chain fatty acids. 16S rRNA amplicon sequencing showed that the gut microbiota dysbiosis in mice was characterized by significant enrichment of six bacterial taxonomic units, including Prevotellaceae, Escherichia Shigella, Alloprevotella, Escherichia coli, Bacteroides vulgatus, and Lachnospiraceae bacterium DW59, which was correlated with immune end points. Using a label-free proteomics quantitative approach, 24 differentially expressed proteins linking GA-induced gut dysbiosis were identified, with four of them enriched in the serine endopeptidase inhibitor activity pathway. The development of GA in mice was associated with changes in specific intestinal luminal factors and may be mediated by serine protease activity-associated metabolic routes.

The high dose of inulin exacerbated food allergy through the excess accumulation of short-chain fatty acids in a BABL/c mouse model.

Inulin dietary supplement is conventionally beneficial to gut health and can potentially prevent food allergy (FA). This study aimed to determine how dietary inulin interventions at different doses affect the OVA-induced FA in a BALB/c mouse model. Although the middle dose of inulin (50 mg per mouse) showed the best therapeutic effect on FA, high-inulin supplementation (80 mg per mouse) provoked severe allergic and intestinal inflammatory responses, which were characterized by elevated serum allergic inflammation-related factor levels, dysfunctional gut barrier, unbalanced luminal pH value, decrease in intestinal antioxidant capacity, and disordered gut microecology. Moreover, profiling of SCFAs indicated that the high-inulin-induced excess accumulation of SCFAs in the colon was responsible for the gut immune disorders. Spearman correlation analysis unraveled that the featured bacterial taxa in the high-inulin-treated mice were Ruminococcaceae and Bifidobacterium, of which the relative abundance was negatively correlated with expression of tight junction proteins and improvement of T cell homeostasis, and positively correlated with levels of allergic inflammation-related indexes. Our work suggested that high-inulin dietary supplementation can be detrimental to allergic individuals and highlighted the importance for personalized use of inulin-type dietary supplements to safely improve human health.

Increasing the pressure during high pressure homogenization regulates the starch digestion of the resulting pea starch-gallic acid complexes.

The pea starch-gallic acid (PS-GA) complexes were prepared using high pressure homogenization (HPH), then the effect and underlying mechanism of pressure on multi-scale structure and digestibility of complexes were investigated. Results showed that HPH promoted the formation of PS-GA complexes, reaching the maximum complex index of 7.74 % at the pressure of 90 MPa, and the main driving force were hydrophobic interactions and hydrogen bonding. The interaction between PS and GA facilitated the formation of surface reticular structures to encapsulate gallic acid molecules, further entangled into bigger size aggregates. The enhancement of rearrangement and aggregation of starch chains during HPH developed a dense hierarchical structure of PS-GA complexes, including short-range ordered structure, V-type crystal structure, lamellar and fractal structure, thus increasing gelatinization temperature. The digestibility of PS-GA complexes substantially changed in reducing rapidly digestible starch content from 29.67 % to 17.07 %, increasing slowly digestible starch from 53.69 % to 56.25 % and resistant starch from 16.63 % to 26.67 %, respectively. Moreover, the resulting complexes exhibited slower digestion rates compared with native PS. Furthermore, the regulating mechanism of pressure during HPH on starch digestibility was the formation of ordered multi-scale structure and inhibition of GA on digestive enzymes.

Intestinal microenvironment-mediated allergic dynamic phenotypes and endotypes in the development of gluten allergy.

This study aimed to investigate the dynamic changes in intestinal microenvironment factors in the development of gluten-induced allergy (GA). Our results showed that GA provoked increasingly severe allergic phenotypes such as allergic and diarrheal symptoms with the gluten sensitization frequency, which was accompanied by dynamically rising levels of gluten-specific immunoglobulin (Ig) E, IgG2a and IgA, serum histamine, T cell-related inflammatory cytokines, and intestinal indexes. An increase in luminal pH was more significant in the large intestine versus the small intestine, which was due to a dynamic decline in colonic short-chain fatty acid levels. Both antioxidant capacity and intestinal permeability in the large intestine varied with the GA severity, as evidenced by a dynamic increase in the malondialdehyde content and a decrease in the superoxide dismutase activity and total antioxidant capacity. Moreover, we demonstrated that intestinal microenvironment dysbiosis occurred before a true allergy reaction began. Spearman correlation analysis suggested that the characteristic bacterial cluster, namely Alistipes, Desulfovibrio, Ileibacterium, Parabacteroides, and Ruminococcus torques group, are essential in the association between GA and intestinal microenvironment homeostasis.

Tilapia (Oreochromis mossambicus) allergens characterized by ELISA, SDS-PAGE, 2D gels, Western blotting and MALDI-TOF mass spectrometry.

Parvalbumins have long been identified as major allergens in fish, but our research has found that parvalbumins are not the main cause of allergic reactions to tilapia. After homogenization, proteins were extracted from freshwater tilapia to react with a pooled sera sample taken from patients (n = 20) tested to be allergic to tilapia. Enzyme-linked immunosorbent assay revealed immunoglobulin E antibody activity, followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis, Western blot, 2D electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to carry out protein separation and analysis. Protein identification against different databases yielded three known high molecular weight proteins as tilapia allergens: chromosome undetermined SCAF7145, fructose-bisphosphate aldolase A and enolase 3 (beta muscle). A fourth, new, unidentified protein with two T-cell receptors was discovered.

Potato starch films by incorporating tea polyphenol and MgO nanoparticles with enhanced physical, functional and preserved properties.

Due to the massive environmental pollution caused by synthetic plastic packaging accumulation and contemporary necessities of food packaging materials, the biodegradable and multifunctional bionanocomposite films based on potato starch (PS) incorporating tea polyphenol (TP) and MgO nanoparticles (MgO-NPs) were successfully fabricated by the solution casting method, and their physical and functional properties and application in fruits preservation were systematically investigated. Incorporation of TP and MgO-NPs improved the films' tensile strength, UV light-blocking, hydrophobicity and thermal stability, and decreased their moisture content (from 14.02 % to 11.21 %), water solubility (from 19.57 % to 16.56 %), and water vapor permeability (from 17.32 to 9.07 × 10-11 g∙m-1∙s-1∙Pa-1). Moreover, the PS/TP/MgO-NPs films exhibited strong antioxidant activity, and remarkable antibacterial activity against Escherichia coli and Staphylococcus aureus with the diameter of inhibition zone of 25.60 mm and 27.50 mm, respectively. SEM, ATR-FTIR and XRD analyses indicated the TP and MgO-NPs were dispersed homogeneously in the PS matrix, and identified the molecular interactions of hydrogen bond, hydrophobic interaction and electrostatic attraction. Biodegradability assessment showed that all the films were rapidly decomposed within ~20 days under simulated environmental conditions. Compared to control, the PS/TP/MgO-NPs film-forming solution coatings were capable of maintaining fruit quality by reducing the change in weight loss, firmness and total soluble solids. Overall, these results suggested that the multifunctional bionanocomposite films could be a potential approach for developing sustainable active food packaging.

Gut Microbial Signatures Associated with Peanut Allergy in a BALB/c Mouse Model.

Multiple studies have uncovered the pivotal role of gut microbiota in the development of food allergy. However, the effects of gut microbiota on peanut allergy are still unclear. Here, we characterized the gut microbiota composition of peanut-allergic mice by 16S rRNA sequencing and analyzed the correlation between allergic indicators and gut microbiota composition. Outcomes showed that the gut microbiota composition was reshaped in peanut-allergic mice, with Acidobacteriota, Lachnospiraceae, Rikenellaceae, Alistipes, Lachnospiraceae_NK4A136_group significantly down-regulated and Muribaculaceae up-regulated. All of them were significantly correlated with the serum peanut-specific antibodies. These results suggested that these six bacterial OTUs might be the gut microbial signatures associated with peanut allergy.

Pediococcus acidilactici Strain Alleviates Gluten-Induced Food Allergy and Regulates Gut Microbiota in Mice.

Wheat flour, the most important source of food globally, is also one of the most common causative agents of food allergy. Wheat gluten protein, which accounts for 80% of the total wheat protein, is a major determinant of important wheat-related disorders. In this study, the effects of Pediococcus acidilactici XZ31 against gluten-induced allergy were investigated in a mouse model. The oral administration of P. acidilactici XZ31 attenuated clinical and intestinal allergic responses in allergic mice. Further results showed that P. acidilactici XZ31 regulated Th1/Th2 immune balance toward Th1 polarization, which subsequently induced a reduction in gluten-specific IgE production. We also found that P. acidilactici XZ31 modulated gut microbiota homeostasis by balancing the Firmicutes/Bacteroidetes ratio and increasing bacterial diversity and the abundance of butyrate-producing bacteria. Specifically, the abundance of Firmicutes and Erysipelotrichaceae is positively correlated with concentrations of gluten-specific IgE and may act as a fecal biomarker for diagnosis. The evidence for the role of P. acidilactici XZ31 in alleviating gluten-induced allergic responses sheds light on the application of P. acidilactici XZ31 in treating wheat allergy.

Agronomic Traits, Fresh Food Processing Characteristics and Sensory Quality of 26 Mung Bean (Vigna radiata L.) Cultivars (Fabaceae) in China.

In recent years, with the expansion of mung bean (Vigna radiata L.) planting areas and the increase of consumer demand, it has become imperative to screen high-quality mung bean cultivars. In this study, the agronomic traits, fresh bean characteristics, and sensory evaluation of boiled beans were analyzed for 26 mung bean cultivars. The results showed that the variation coefficient and genetic diversity index of six agronomic traits of mung bean ranged from 9.04% to 44.98%, 1.68 to 1.96, respectively, with abundant genetic variation, and the highest was the grain yield. Mung bean cultivars with higher grain yield had more advantage in the number of branches, number of pods per plant, and 100-seed weight. The fresh bean traits were relatively stable, with an average coefficient variation of 8.48%. The trait with the highest genetic diversity index was the number of seeds per pod (2.03). The cultivar with the highest total sensory evaluation score of boiled beans was Zhanglv 3 (75.67), which had more advantages in taste and color. Through the comprehensive evaluation of grey relational analysis, the cultivars suitable for fresh food processing were Zhonglv 3 (0.960), Jilv 11 (0.942), Zhonglv 1 (0.915), CES-78 (0.899) and Kelv 2 (0.896). Generally, the high-quality cultivars with higher yield and fresh food processing characteristics were CES-78, Kelv 2, Zhonglv 16, and Zhonglv 2. This study provided a preference for the breeding of fresh mung bean cultivars, development of new products and improvement of mung bean resource utilization.

Molecular Basis of IgE-Mediated Shrimp Allergy and Heat Desensitization.

Crustacean allergy, especially to shrimp, is the most predominant cause of seafood allergy. However, due to the high flexibility of immunoglobulin E (IgE), its three-dimensional structure remains unsolved, and the molecular mechanism of shrimp allergen recognition is unknown. Here a chimeric IgE was built in silico, and its variable region in the light chain was replaced with sequences derived from shrimp tropomyosin (TM)-allergic patients. A variety of allergenic peptides from the Chinese shrimp TM were built, treated with heating, and subjected to IgE binding in silico. Amino acid analysis shows that the amino acid residue conservation in shrimp TM contributes to eliciting an IgE-mediated immune response. In the shrimp-allergic IgE, Glu98 in the light chain and other critical residues that recognize allergens from shrimp are implicated in the molecular basis of IgE-mediated shrimp allergy. Heat treatment could alter the conformations of TM allergenic peptides, impact their intramolecular hydrogen bonding, and subsequently decrease the binding between these peptides and IgE. We found Glu98 as the characteristic amino acid residue in the light chain of IgE to recognize general shrimp-allergic sequences, and heat-induced conformational change generally desensitizes shrimp allergens.

Co-culture fermentation of Pediococcus acidilactici XZ31 and yeast for enhanced degradation of wheat allergens.

Previous researchers have shown the potential of sourdough and isolated lactic acid bacteria in reducing wheat allergens. As the interactions of lactic acid bacteria with yeast is a key event in sourdough fermentation, we wished to investigate how yeast affects metabolism of lactic acid bacteria, thereby affecting protein degradation and antigenic response. In this study, three strains isolated from sourdough were selected for dough fermentation, namely Pediococcus acidilactici XZ31, Saccharomyces cerevisiae JM1 and Torulaspora delbrueckii JM4. The changes in dough protein during the fermentation process were studied. Protein degradation and antigenic response in dough inoculated with Pediococcus acidilactici XZ31 monoculture and co-culture with yeast were mainly evaluated by SDS-PAGE, immunoblotting, ELISA and Liquid chromatography-tandem mass spectrometry assay. The whole-genome transcriptomic changes in Pediococcus acidilactici XZ31 were also investigated by RNA sequencing. The results showed that water/salt soluble protein and Tri a 28/19 allergens content significantly decreased after 24 h fermentation. Co-culture fermentation accelerated the degradation of protein, and reduced the allergen content to a greater extent. RNA-sequencing analysis further demonstrated that the presence of yeast could promote protein metabolism in Pediococcus acidilactici XZ31 for a certain period of time. These results revealed a synergistic effect between Pediococcus acidilactici XZ31 and yeast degrading wheat allergens, and suggested the potential use of the multi-strain leavening agent for producing hypoallergenic wheat products.

Thermal and Acidic Treatments of Gluten Epitopes Affect Their Recognition by HLA-DQ2 in silico.

Celiac disease (CD) is a prevalent disorder with autoimmune features. Dietary exposure of wheat gluten (including gliadins and glutenins) to the small intestine activates the gluten-reactive CD4+ T cells and controls the disease development. While the human leukocyte antigen (HLA) is the single most important genetic factor of this polygenic disorder, HLA-DQ2 recognition of gluten is the major biological step among patients with CD. Gluten epitopes are often rich in Pro and share similar primary sequences. Here, we simulated the solution structures changes of a variety of gluten epitopes under different pH and temperatures, to mimic the fermentation and baking/cooking processes. Based on the crystal structure of HLA-DQ2, binding of differently processed gluten epitopes to DQ2 was studied in silico. This study revealed that heating and pH change during the fermentation process impact the solution structure of gluten epitope. However, binding of differently treated gluten epitope peptide (GEP) to HLA-DQ2 mainly depended on its primary amino acid sequence, especially acidic amino acid residues that play a pivotal role in their recognition by HLA-DQ2.