Limited hydrolysis combined with controlled Maillard-induced glycation does not reduce immunoreactivity of soy protein for all sera tested

Establishment of DAS-ELISA and lateral flow immunochromatography for the detection of peanut allergen Ara h 3 after heat-moisture treatment

Peanuts are highly nutritious but pose a significant risk of triggering food allergies. While heat treatment can reduce the allergenicity of many foods, it may also alter their structure, potentially impacting detection results. This study employed double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and lateral flow immunochromatography (LFIA) to evaluate the allergen Ara h 3 following heat-moisture treatment. DAS-ELISA achieved a detection limit of 39.06 ng/mL, with inter-plate and intra-plate coefficients of variation below 3.05 % and 6.79 %, respectively, and recovery rates ranging from 78.48 % to 90.93 %. LFIA, with a detection limit of 1.6 μg/mL, demonstrated high sensitivity, stability, and no cross-reactivity with other proteins. Both methods were effective in detecting peanut-processed products, with heat-moisture treatment significantly reducing Ara h 3 antigenicity, making them valuable tools for assessing desensitization in food production.

Localization of G3A1b Destroyed by Heat Treatment and Identification of Allergenic Amino Acids

The G3 subunit is a key allergenic component of glycinin, a major soybean protein. This study utilized molecular cloning and recombinant phage construction to investigate antigenic sites in the G3 subunit that are denatured during heat treatment. Using indirect ELISA, the G3A1b-3-B-II fragment was identified as the denatured antigenic site, further localized to the sequence 236RQIVRKLQGENEEEEKGAIVTVKGGLSV263 through three rounds of screening. Alanine-scanning mutagenesis revealed that residues V255, T256, V257, G259, and L261 are critical for the binding of synthetic peptide P3 (251KGAIVTVKGGLSV263) to IgG and IgE. These findings provide a refined understanding of the amino acid residues that influence glycinin allergenicity. This research lays the groundwork for reducing or eliminating soybean allergenicity through targeted amino acid substitutions, advanced biological breeding techniques, and other interventions. This method overcomes the defect that heat treatment cannot completely eliminate the allergenicity of glycinin.

Recent advances in the modification of soy proteinase: Enzyme types, structural and functional characteristics, and applications in foods

Soy protein, as the major component of soybean, has important applications in food, medicine and materials. This review summarizes the research progress in the technology of enzymatic modification of soy protein, focusing on the principles and applications of enzymatic hydrolysis and enzymatic cross-linking. Enzymatic modification can modulate the structure and properties of soy protein, providing a theoretical basis for its wide application in the food industry. The functional properties of soy protein are closely related to its structure. Enzyme-modified soy protein can be improved in terms of solubility, emulsification, water and oil retention, and gel properties. The enzyme modification technology is highly specific, safe and mild and provides new ideas for functional improvement of soy protein. However, in practical applications, enzymatic modification still has problems such as poor control of the degree of hydrolysis. Therefore, in the future, the effects of different types of enzymes and modification methods on soy protein, as well as efficient and targeted regulatory mechanisms, can be further explored to make it more widely used in food, medicine and materials.

Combined processing technologies: Promising approaches for reducing Allergenicity of food allergens

Food allergy is a severe threat to human health. Although processing technologies are widely used to reduce allergenicity, hypoallergenic foods produced by a single processing technology cannot satisfy consumer demands. Combined processing technology (CPT) is a promising strategy for efficiently producing high-quality hypoallergenic foods. This paper reviews the effects of CPT on the allergenicity of food allergens from three aspects: physical-biochemical CPT, biochemical-biochemical CPT, and physical-physical CPT. The synergistic mechanisms, strengths, and limitations of these technologies were discussed. It was found that CPT is generally more effective than single-processing technologies. Physical-biochemical CPT is the most widely studied and well-established because physical and biochemical processing technologies complement each other and effectively disrupt conformational and linear epitopes. Biochemical-biochemical CPT primarily disrupts linear epitopes, but most methods are time-consuming. Physical-physical CPT is the least studied; they mainly disrupt conformational epitopes and only rarely affect linear epitopes.

Integration of glutathione disulfide-mediated extraction and capillary electrophoresis for determination of Cd(II) and Pb(II) in edible oils

A novel method is introduced for extracting and enriching Cd(II) and Pb(II) from edible oils using glutathione disulfide (GSSG) as both an extractant and a phase-separation agent. The ions in the oils were initially extracted into an aqueous solution containing GSSG. After mixing the solution with acetonitrile at the appropriate volume ratio, a new phase formed, resulting in enrichment of the analytes. The experimental conditions were optimized using response surface methodology with a central composite design. Under optimal conditions, the method offered a combined enrichment factor of >660, with combined extraction efficiencies of 84.31% and 83.35% for Cd(II) and Pb(II), respectively. Finally, the method was conjugated to capillary electrophoresis to determine Cd(II) and Pb(II) in edible oil samples, with detection limits of 0.45 and 1.24 ppb, respectively. In comparison to traditional approaches, the GSSG-based method demonstrates rapidity, efficiency, and recyclability in extracting heavy metal ions from complex matrices.

Emerging Chemical, Biochemical, and Non-Thermal Physical Treatments in the Production of Hypoallergenic Plant Protein Ingredients

Allergies towards gluten and legumes (such as, soybean, peanut, and faba bean) are a global issue and, occasionally, can be fatal. At the same time, an increasing number of households are shifting to plant protein ingredients from these sources, which application and consumption are limited by said food allergies. Children, the elderly, and people with immune diseases are particularly at risk when consuming these plant proteins. Finding ways to reduce or eliminate the allergenicity of gluten, soybean, peanut, and faba bean is becoming crucial. While thermal and pH treatments are often not sufficient, chemical processes such as glycation, polyphenol conjugation, and polysaccharide complexation, as well as controlled biochemical approaches, such as fermentation and enzyme catalysis, are more successful. Non-thermal treatments such as microwave, high pressure, and ultrasonication can be used prior to further chemical and/or biochemical processing. This paper presents an up-to-date review of promising chemical, biochemical, and non-thermal physical treatments that can be used in the food industry to reduce or eliminate food allergenicity.

Lactic acid bacteria modulate the gastrointestinal digestive behavior of soy glycinin and correlation with its immunoreactivity: a peptidomic study

Lactic acid bacterial fermentation helps reduce the immunoreactivity of soy protein. Nevertheless, the effect of lactic acid bacterial fermentation on a particular soy allergen and the consequent dynamic change of epitopes during gastrointestinal digestion are unclear. In this study, soy glycinin was isolated and an in vitro dynamic gastrointestinal model was established to investigate the dynamic change in the immunoreactivity and peptide profile of unfermented (UG) and fermented glycinin (FG) digestates. The results demonstrated that the FG intestinal digestate had a lower antigenicity (0.08%-0.12%) and IgE-binding capacity (1.49%-3.61%) towards glycinin at the early (I-5) and middle (I-30) stages of gastrointestinal digestion, especially those prepared at 2% (w/v) protein concentration. Peptidomic analysis showed that the glycinin subunits G1 and G2 were the preferred ones to release the most abundant peptides, whereas G2, G4, and G5 had an elevated epitope-cleavage rate in FG at stages I-5 and I-30. Three-dimensional modeling revealed that fermentation-induced differential degradation epitopes in gastrointestinal digestion were predominantly located in the α-helix and β-sheet structures. They were closely correlated with the reduced immunoreactivity of soy glycinin.

Modulation of soy protein immunoreactivity by different matrix structures of lactic acid bacterium-induced soy protein gels: Epitope destruction during in vitro gastroduodenal digestion and absorption

Soy allergy is a common health problem. Food structure may change the gastroduodenal digestion and absorption of soy proteins, thus leading to the modulation of the immunoreactivity of soy proteins. In this study, lactic acid bacterium (LAB)-fermented soy protein isolates (FSPIs) were prepared at four concentrations (0.2 %-5.0 %, w/v) to present various matrix structures (nongel, NG; weak gel, WG; medium gel, MG; and firm gel, FG) and subjected to in vitro dynamic gastroduodenal digestion model. The results of sandwich enzyme-linked immunosorbent and human serum IgE binding capacity assays demonstrated that FSPI gels, especially the FSPI-MG/WG digestates obtained at the early and medium stages of duodenal digestion (D-5 and D-30), possessed greater potency in immunoreactivity reduction than FSPI-NG and reduced to 1.9 %-68.3 %. The transepithelial transport study revealed that the immunoreactivity of FSPI-MG/WG D-5 and D-30 digestates decreased through the stimulation of interferon-γ production and the induction of dominant Th1/Th2 differentiation. Peptidomics and bioinformatics analyses illustrated that compared with FSPI-NG, the FSPI-gel structure promoted the epitope degradation of the major allergens glycinin G2/G5, β-conglycinin α/β subunit, P34, lectin, trypsin inhibitor, and basic 7S globulin. Spatial structure analysis showed that FSPI-gel elicited an overall promotion in the degradation of allergen epitopes located in interior and exterior regions and was dominated by α-helix and β-sheet secondary structures, whereas FSPI-MG/WG promoted the degradation of epitopes located in the interior region of glycinin/β-conglycinin and exterior region of P34/basic 7S globulin. This study suggested that the FSPI-gel structure is a promising food matrix for decreasing the allergenic potential of allergenic epitopes during gastroduodenal digestion and provided basic information on the production of hypoallergenic soy products.

Composition, functional properties, health benefits and applications of oilseed proteins: A systematic review

Common oilseeds, such as soybean, peanut, rapeseed, sunflower seed, sesame seed and chia seed, are key sources of edible vegetable oils. Their defatted meals are excellent natural sources of plant proteins that can meet consumers' demand for health and sustainable substitutes for animal proteins. Oilseed proteins and their derived peptides are also associated with many health benefits, including weight loss and reduced risks of diabetes, hypertension, metabolic syndrome and cardiovascular events. This review summarizes the current status of knowledge on the protein and amino acid composition of common oilseeds as well as the functional properties, nutrition, health benefits and food applications of oilseed protein. Currently, oilseeds are widely applied in the food industry regarding for their health benefits and good functional properties. However, most oilseed proteins are incomplete proteins and their functional properties are not promising compared to animal proteins. They are also limited in the food industry due to their off-flavor, allergenic and antinutritional factors. These properties can be improved by protein modification. Therefore, in order to make better use of oilseed proteins, methods for improving their nutrition value, bioactive activity, functional and sensory characteristics, as well as the strategies for reducing their allergenicity were also discussed in this paper. Finally, examples for the application of oilseed proteins in the food industry are presented. Limitations and future perspectives for developing oilseed proteins as food ingredients are also pointed out. This review aims to foster thinking and generate novel ideas for future research. It will also provide novel ideas and broad prospects for the application of oilseeds in the food industry.

Enhancement of pea protein solubility and thermal stability for acidic beverage applications via endogenous Maillard-induced glycation and chromatography purification

A clean-label process to endogenously glycate and purify pea protein was investigated. The production of maltodextrin from pea starch with a specific dextrose equivalent (DE) was optimized. The produced maltodextrin (14.6 DE) was used to initiate a limited and controlled Maillard-induced glycation of pea protein. The partially glycated pea protein (PG-PP) was subjected to hydrophobic interaction chromatography to remove unreacted carbohydrate, followed by characterization of the purified product. The extent of Maillard-induced glycation was monitored by assessing changes in color, free amino groups, and protein/glycoprotein profiles. The purified PG-PP was evaluated for thermal denaturation, surface properties, protein secondary structure, protein solubility, thermal stability, and digestibility. Maillard-induced glycation was limited to initial stages and resulted in a moderate blockage of amine groups (∼30%). The purified PG-PP had a relatively low surface hydrophobicity, a markedly enhanced protein solubility (∼90%) at pH 3.4, and a nonimpacted protein in vitro digestibility (∼100%). This work provided the impetus needed for future scale-up and process optimization for the production of value-added pea protein ingredient intended for high protein beverage applications.

Bioactive and health-promoting properties of enzymatic hydrolysates of legume proteins: a review

This study comprehensively reviewed the effect of controlled enzymatic hydrolysis on the bioactivity of pulse protein hydrolysates (PPHs). Proteolysis results in the partial structural unfolding of pulse proteins with an increase in buried hydrophobic groups of peptide sequences. The use of PPHs in a dose-dependent manner can enhance free radical scavenging and improve antioxidant activities regarding inhibition of lipid oxidation, ferric reducing power, metal ion chelation, and β-carotene bleaching inhibition. Ultrafiltered peptide fractions with low molecular weights imparted angiotensin-I converting enzyme (ACE) inhibitory effects during in vitro simulated gastrointestinal digestion and in vivo conditions. Ultrasonication, high-pressure pretreatments, and glycosylation as post-treatments can improve the antiradical, antioxidant, and ACE inhibitory activities of PPHs. The electrostatic attachment of pulse peptides to microbial cells can inhibit the growth and activity of bacteria and fungi. Bioactive pulse peptides can reduce serum cholesterol and triglycerides, and inhibit the formation of adipocyte lipid storage, allergenic factors, inflammatory markers, and arterial thrombus without cytotoxicity. The combination of germination and enzymatic hydrolysis can significantly increase the protein digestibility and bioavailability of essential amino acids. Moreover, the utilization and enrichment of bakery and meat products with functional PPHs ensure quality, safety, and health aspects of food products.

Process Modelling and Simulation of Key Volatile Compounds of Maillard Reaction Products Derived from Beef Tallow Residue Hydrolysate Based on Proxy Models

The hydrolysis time is directly related to the flavor of the Maillard reaction, but existing proxy models cannot simulate and model the variation curves of vital volatile components. This study developed a predictive model for modelling and simulating key volatile compounds of Maillard reaction products (MRPs) derived from beef tallow residue hydrolysate. Results showed the degree of hydrolysis increased with hydrolysis time, and the most significant improvement in the roast flavor and overall acceptance was when hydrolyzing 4 h. Based on flavor dilution value and the relative odor activity value, nine key volatile components were identified, and 2-ethyl-3,5-dimethylpyrazine with roast flavor was the highest. Compared with Polynomial Curve Fitting (PCF) and Cubic Spline Interpolation (CSI), key volatile compounds of MRPs could be better modeled and simulated by the Curve Prediction Model (CPM). All results suggested that CPM could predict the changes in key volatile components produced by MRPs.

Investigation of differences in allergenicity of protein from different soybean cultivars through LC/MS-MS

Soybean allergy is a health-threatening issue and identifying raw soybeans with low allergenicity is important for producing hypoallergenic soybean products. Soybean allergy is mainly triggered by soybean proteins. In this study, the protein profiles, allergen compositions, and epitopes in protein from different soybean cultivars (R1, R2 and R3) were evaluated by SDS-PAGE and LC/MS-MS, and their allergenicity was assessed by indirect ELISA and Western blot analysis using the serum IgE of patients allergic to soybeans. The lowest allergenicity was observed in R3, probably resulting from the low concentration of Gly m 4-Gly m 6. The allergenicity of soybeans is affected by multiple allergens rather than a single allergen. Venn diagram, PCA, heatmap, and peptide map analyses have shown the differences in protein and peptide profiles among soybean proteins from different soybean cultivars. Epitope analysis further demonstrated that low contents of dominant epitopes in Gly m 4 and Gly m 5 contributed to low allergenicity in R3, although R3 contained high contents of no-dominant epitopes.

Endopeptidases, exopeptidases, and glutamate decarboxylase in soybean water extract and their in vitro activity

The proteolytic activity of some soybean endogenous proteases have been clarified in the previous studies, but the information concerning the roles of these proteases and some other unknown ones during soybean processing are scarce. Herein, 16 endopeptidases, 13 exopeptidases, 24 inhibitors (two serpin-ZX and one subtilisin inhibitor firstly identified), and one glutamate decarboxylase were identified in the soybean water extract by the liquid chromatography tandem mass spectrometry analysis. Amongst the identified endopeptidases, just the aspartic endopeptidases (optimal at pH 2.5-3 and 35-45 °C) showed the detectable proteolytic activity by the tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis and protease inhibitor assay analyses, whereas serine, cysteine, and metallo- endopeptidases (except P34 probable thiol protease) did not. Free amino acid analysis showed that the exopeptidases and glutamate decarboxylase were optimal at pH 6 and 45 °C, and by 6 h incubation, the free amino acids and γ-aminobutyric acid almost doubled.

Efficient encapsulation of fish oil: Capitalizing on the unique inherent characteristics of whey cream and hydrolyzed whey protein

The effects of protein concentration and of blending a phospholipid-rich whey coproduct, Procream (Salibra 700 Procream, Glanbia Nutritionals), with intact or hydrolyzed whey protein concentrate, on fish oil microencapsulation efficiency and oxidative stability were assessed. Trypsin and protease M, from Aspergillus oryzae, were used to produce 2 unique hydrolysates. All microcapsules had excellent encapsulation efficiencies (>92%) and good physical properties, regardless of protein content and Procream inclusion. Intact α-lactalbumin and β-lactoglobulin and their peptides were involved in stabilizing oil droplets. Disulfide interchange resulted in formation of protein aggregates, which were more pronounced in samples containing Procream. Although all microcapsules had relatively good oxidative stability, most had better stability at 2 versus 0.5% protein. Protease M hydrolysate + Procream microcapsules had the highest stability, regardless of protein content. Results demonstrated that Procream, at a reduced protein inclusion level, can partially replace more expensive whey protein ingredients in microencapsulation, when blended with a select hydrolysate.

Glycation of Plant Proteins Via Maillard Reaction: Reaction Chemistry, Technofunctional Properties, and Potential Food Application

Plant proteins are being considered to become the most important protein source of the future, and to do so, they must be able to replace the animal-derived proteins currently in use as techno-functional food ingredients. This poses challenges because plant proteins are oftentimes storage proteins with a high molecular weight and low water solubility. One promising approach to overcome these limitations is the glycation of plant proteins. The covalent bonding between the proteins and different carbohydrates created via the initial stage of the Maillard reaction can improve the techno-functional characteristics of these proteins without the involvement of potentially toxic chemicals. However, compared to studies with animal-derived proteins, glycation studies on plant proteins are currently still underrepresented in literature. This review provides an overview of the existing studies on the glycation of the major groups of plant proteins with different carbohydrates using different preparation methods. Emphasis is put on the reaction conditions used for glycation as well as the modifications to physicochemical properties and techno-functionality. Different applications of these glycated plant proteins in emulsions, foams, films, and encapsulation systems are introduced. Another focus lies on the reaction chemistry of the Maillard reaction and ways to harness it for controlled glycation and to limit the formation of undesired advanced glycation products. Finally, challenges related to the controlled glycation of plant proteins to improve their properties are discussed.

Assessment of the effect of lactic acid fermentation on the gastroduodenal digestibility and immunoglobulin E binding capacity of soy proteins via an in vitro dynamic gastrointestinal digestion model

Fermentation by lactic acid bacteria is helpful in reducing soy protein immunoreactivity. However, how lactic acid fermentation influences the gastroduodenal digestibility and immunoglobulin E (IgE) binding capacity of soy proteins remains unclear. In this study, the protein digestion of a fermented soybean protein isolate (FSPI) was investigated and compared with that of a soybean protein isolate (SPI). The effect on their respective IgE binding capacities at the gastric and duodenal phases was also explored by using a novel in vitro dynamic gastrointestinal digestion model (Bionic Rat Model II+). Medium pH was measured, microstructural analysis was performed, peptide distribution and free amino acid content were determined, and SDS-PAGE analysis was performed to assess the differences between SPI and FSPI. The results showed that FSPI had lower pH (3.76), larger protein aggregates (>60 μm), and higher low-molecular-weight peptides than SPI. During the first 30 min of gastric and duodenal digestion, the extent of hydrolysis of FSPI was higher than that of SPI, and the gastric transition time of the former was longer than that of the latter. Conversely, differences tended to be narrower in the next 30-180 min of gastric and duodenal digestion. As a result, the IgE binding capacity of FSPI was significantly lower than that of SPI at 30 min of gastric and duodenal digestion. Therefore, fermentation by lactic acid bacteria affected the digestibility rate of soy proteins, especially at the initial phases of gastric and duodenal digestion, thereby reducing the exposure of intact epitopes in the duodenum. This study helped to elucidate how lactic acid fermentation affected the digestive behavior of soy proteins and its implication in IgE immunoreactivity reduction.

Process optimization and the relationship between the reaction degree and the antioxidant activity of Maillard reaction products of chicken liver protein hydrolysates

The aim of this study was to optimize the protein hydrolysates from chicken liver with xylose under Maillard reaction (MR) conditions using response surface methodology. The correlation between the browning degree, grafting degree, and the antioxidant activities of the Maillard reaction products (MRPs) was investigated. The optimal reaction conditions were achieved with a reaction temperature of 138.78°C, an initial pH of 7.99, and a reaction time of 93.14 min. The grafting degree (41.98%) and browning degree (2.582) of chicken liver protein hydrolysate MRPs (CLPHM) were notably higher (P < 0.05) than those of protein MRPs (CLPM) and were significantly lower (P < 0.05) than those of sonicated hydrolysate MRPs (SCLPHM). The reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and hydroxyl radical scavenging of CLPM, CLPHM, and SCLPHM were significantly higher (P < 0.01) than those of the protein or hydrolysate substrates. The grafting degree and browning degree of CLPM, CLPHM, and SCLPHM had positive correlations with DPPH and hydroxyl radical scavenging activity. Hence, this study could enhance the added value of chicken liver by exhibiting the enhancements from ultrasound pretreatment and the MR. MRPs could have an effective and potential application in the food industry.

Effects of different satiety levels on the fate of soymilk protein in gastrointestinal digestion and antigenicity assessed by an in vitro dynamic gastrointestinal model

The effects of different satiety levels on soymilk protein digestion and antigenicity have been evaluated by an in vitro dynamic gastrointestinal model.

Inhibition of soluble epoxide hydrolase attenuates eosinophil recruitment and food allergen-induced gastrointestinal inflammation

Prevalence of food allergies in the United States is on the rise. Eosinophils are recruited to the intestinal mucosa in substantial numbers in food allergen-driven gastrointestinal (GI) inflammation. Soluble epoxide hydrolase (sEH) is known to play a pro-inflammatory role during inflammation by metabolizing anti-inflammatory epoxyeicosatrienoic acids (EETs) to pro-inflammatory diols. We investigated the role of sEH in a murine model of food allergy and evaluated the potential therapeutic effect of a highly selective sEH inhibitor (trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]-cyclohexyloxy}-benzoic acid [t-TUCB]). Oral exposure of mice on a soy-free diet to soy protein isolate (SPI) induced expression of intestinal sEH, increased circulating total and antigen-specific IgE levels, and caused significant weight loss. Administration of t-TUCB to SPI-challenged mice inhibited IgE levels and prevented SPI-induced weight loss. Additionally, SPI-induced GI inflammation characterized by increased recruitment of eosinophils and mast cells, elevated eotaxin 1 levels, mucus hypersecretion, and decreased epithelial junction protein expression. In t-TUCB-treated mice, eosinophilia, mast cell recruitment, and mucus secretion were significantly lower than in untreated mice and SPI-induced loss of junction protein expression was prevented to variable levels. sEH expression in eosinophils was induced by inflammatory mediators TNF-α and eotaxin-1. Treatment of eosinophils with t-TUCB significantly inhibited eosinophil migration, an effect that was mirrored by treatment with 11,12-EET, by inhibiting intracellular signaling events such as ERK (1/2) activation and eotaxin-1-induced calcium flux. These studies suggest that sEH induced by soy proteins promotes allergic responses and GI inflammation including eosinophilia and that inhibition of sEH can attenuate these responses.