Immunoreactivity of wheat proteins modified by hydrolysis and polymerisation

Current challenges of alternative proteins as future foods

Global demand for food is expected to nearly double by 2050. Alternative proteins (AP) have been proposed as a sustainable solution to provide food security as natural resources become more depleted. However, the growth and consumer intake of AP remains limited. This review aims to better understand the challenges and environmental impacts of four main AP categories: plant-based, insect-based, microbe-derived, and cultured meat and seafood. The environmental benefits of plant-based and insect-based proteins have been documented but the impacts of microbe-derived proteins and cultured meat have not been fully assessed. The development of alternative products with nutritional and sensory profiles similar to their conventional counterparts remains highly challenging. Furthermore, incomplete safety assessments and a lack of clear regulatory guidelines confuse the food industry and hamper progress. Much still needs to be done to fully support AP utilization within the context of supporting the drive to make the global food system sustainable.

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.

Reducing Immunoreactivity of Gluten Peptides by Probiotic Lactic Acid Bacteria for Dietary Management of Gluten-Related Diseases

Immunoreactive gluten peptides that are not digested by peptidases produced by humans can trigger celiac disease, allergy and non-celiac gluten hypersensitivity. The aim of this study was to evaluate the ability of selected probiotic strains to hydrolyze immunoreactive gliadin peptides and to identify peptidase-encoding genes in the genomes of the most efficient strains. Residual gliadin immunoreactivity was measured after one- or two-step hydrolysis using commercial enzymes and bacterial peptidase preparations by G12 and R5 immunoenzymatic assays. Peptidase preparations from Lacticaseibacillus casei LC130, Lacticaseibacillus paracasei LPC100 and Streptococcus thermophilus ST250 strains significantly reduced the immunoreactivity of gliadin peptides, including 33-mer, and this effect was markedly higher when a mixture of these strains was used. In silico genome analyses of L. casei LC130 and L. paracasei LPC100 revealed the presence of genes encoding peptidases with the potential to hydrolyze bonds in proline-rich peptides. This suggests that L. casei LC130, L. paracasei LPC100 and S. thermophilus ST250, especially when used as a mixture, have the ability to hydrolyze immunoreactive gliadin peptides and could be administered to patients on a restricted gluten-free diet to help treat gluten-related diseases.

A review of gluten detoxification in wheat for food applications: approaches, mechanisms, and implications

With the improved knowledge of gluten-related disorders, especially celiac disease (CD), the market of gluten-free food is growing. However, the current gluten-free diet still presents challenges in terms of nutrition, acceptability, and cost due to the absence of gluten. It is important to note that gluten-related allergies or sensitivities have different underlying causes. And individuals with mild non-celiac gluten disorder symptoms may not necessarily require the same gluten-free treatments. Scientists are actively seeking alternative solutions for these consumers. This review delves into the various strategies employed by researchers for detoxifying gluten or modifying its main protein, gliadin, including genetic treatment, transamidation and deamidation, hydrolysis, and microbial treatments. The mechanisms, constraints of these techniques, their current utilization in food items, as well as their implications for gluten-related disorders, are discussed in detail. Although there is still a gap in the application of these methods as alternative solutions in the real market, the summary provided by our review could be beneficial for peers in enriching their basic ideas and developing more applicable solutions for wheat gluten detoxification.

New Perspectives on Food Matrix Modulation of Food Allergies: Immunomodulation and Component Interactions

Food allergy is a multifactorial interplay process influenced not only by the structure and function of the allergen itself but also by other components of the food matrix. For food, before it is thoroughly digested and absorbed, numerous factors make the food matrix constantly change. This will also lead to changes in the chemistry, biochemical composition, and structure of the various components in the matrix, resulting in multifaceted effects on food allergies. In this review, we reveal the relationship between the food matrix and food allergies and outline the immune role of the components in the food matrix, while highlighting the ways and pathways in which the components in the food matrix interact and their impact on food allergies. The in-depth study of the food matrix will essentially explore the mechanism of food allergies and bring about new ideas and breakthroughs for the prevention and treatment of food allergies.

Enzymatic crosslinking and food allergenicity: A comprehensive review

Food allergy has become a major global public health concern. In the past decades, enzymatic crosslinking technique has been employed to mitigate the immunoreactivity of food allergens. It is an emerging non-thermal technique that can serve as a great alternative to conventional food processing approaches in developing hypoallergenic food products, owing to their benefits of high specificity and selectivity. Enzymatic crosslinking via tyrosinase (TYR), laccase (LAC), peroxidase (PO), and transglutaminase (TG) modifies the structural and biochemical properties of food allergens that subsequently cause denaturation and masking of the antigenic epitopes. LAC, TYR, and PO catalyze the oxidation of tyrosine side chains to initiate protein crosslinking, while TG initiates isopeptide bonding between lysine and glutamine residues. Enzymatic treatment produces a high molecular weight crosslinked polymer with reduced immunoreactivity and IgE-binding potential. Crosslinked allergens further inhibit mast cell degranulation due to the lower immunostimulatory potential that assists in the equilibration of T-helper (Th)1/Th2 immunobalance. This review provides an updated overview of the studies carried out in the last decade on the potential application of enzymatic crosslinking for mitigating food allergenicity that can be of importance in the context of developing hypoallergenic/non-allergenic food products.

Reducing Immunoreactivity of Gliadins and Coeliac-Toxic Peptides Using Peptidases from L. acidophilus 5e2 and A. niger

Wheat storage proteins and products of their hydrolysis may cause coeliac sprue in genetically predisposed individuals with high expression of main histocompatibility complex HLA-DQ2 or DQ8, since by consuming wheat, they become exposed to proline- (P) and glutamine (Q)-rich gluten. In bread-making, the hydrolysis of gliadins and coeliac-toxic peptides occurs with varied efficiency depending on the fermentation pH and temperature. Degradation of gliadins catalysed by Lactobacillus acidophilus 5e2 peptidases and a commercial prolyl endopeptidase synthesised by A. niger, carried out at pH 4.0 and 37 °C, reduces the gliadin concentration over 110-fold and decreases the relative immunoreactivity of the hydrolysate to 0.9% of its initial value. Hydrolysis of coeliac-toxic peptides: LGQQQPFPPQQPY (P1) and PQPQLPYPQPQLP (P2) under the same conditions occurs with the highest efficiency, reaching 99.8 ± 0.0% and 97.5 ± 0.1%, respectively. The relative immunoreactivity of peptides P1 and P2 was 0.8 ± 0.0% and 3.2 ± 0.0%, respectively. A mixture of peptidases from L. acidophilus 5e2 and A. niger may be used in wheat sourdough fermentation to reduce the time needed for degradation of proteins and products of their hydrolysis.

Pathogenesis of Celiac Disease and Other Gluten Related Disorders in Wheat and Strategies for Mitigating Them

Wheat is a major cereal crop providing energy and nutrients to the billions of people around the world. Gluten is a structural protein in wheat, that is necessary for its dough making properties, but it is responsible for imparting certain intolerances among some individuals, which are part of this review. Most important among these intolerances is celiac disease, that is gluten triggered T-cell mediated autoimmune enteropathy and results in villous atrophy, inflammation and damage to intestinal lining in genetically liable individuals containing human leukocyte antigen DQ2/DQ8 molecules on antigen presenting cells. Celiac disease occurs due to presence of celiac disease eliciting epitopes in gluten, particularly highly immunogenic alpha-gliadins. Another gluten related disorder is non-celiac gluten-sensitivity in which innate immune-response occurs in patients along with gastrointestinal and non-gastrointestinal symptoms, that disappear upon removal of gluten from the diet. In wheat allergy, either IgE or non-IgE mediated immune response occurs in individuals after inhalation or ingestion of wheat. Following a life-long gluten-free diet by celiac disease and non-celiac gluten-sensitivity patients is very challenging as none of wheat cultivar or related species stands safe for consumption. Hence, different molecular biology, genetic engineering, breeding, microbial, enzymatic, and chemical strategies have been worked upon to reduce the celiac disease epitopes and the gluten content in wheat. Currently, only 8.4% of total population is affected by wheat-related issues, while rest of population remains safe and should not remove wheat from the diet, based on false media coverage.

Impact of food processing and simulated gastrointestinal digestion on gliadin immunoreactivity in rolls

BACKGROUND

The enzymatic modification of wheat proteins during dough fermentation and its digestion as supported by peptidases of microbiological origin can result in the degradation of important peptides in the pathogenesis of coeliac disease. However, baking bread and the high temperature associated with this could change the physicochemical and immunological properties of proteins. Thermal changes in the spatial structure of proteins and their hydrolysis can lead to a masking or degrading of immunoreactive peptides.

RESULTS

The addition of prolyl endopeptidase (PEP), comprising peptidases isolated from Lactobacillus acidophilus 5e2 (LA) or transglutaminase (TG) in the course of fermentation, decreases its immunoreactivity by 83.9%, 51.9% and 18.5%, respectively. An analysis of the fractional composition of gliadins revealed that γ- and ω-gliadins are the proteins most susceptible to enzymatic modification. Hydrolysis of wheat storage proteins with PEP and LA reduces the content of αβ-, γ- and ω-gliadins by 13.7%, 60.2% and 41.9% for PEP and by 22.1%, 43.5% and 36.9% for LA, respectively. Cross-linking of proteins with TG or their hydrolysis by PEP and LA peptidases during the process of forming wheat dough, followed by digesting bread samples with PEP and LA peptidases, decreases the immunoreactivity of bread hydrolysates from 2.4% to 0.02%. The content of peptide detected in polypeptide sequences is 263.4 ± 3.3, 30.9 ± 1.5 and 7.9 ± 0.4 mg kg^-1 in samples of hydrolysates of bread digested with PEP, as produced from dough modified by TG, PEP and LA, respectively.

CONCLUSION

Enzymatic pre-modification of proteins during the process of dough fermentation decreases their immunoreactive potential, such that fewer peptides recognised by R5 antibodies are released during the digestion process from the bread matrix. Immunoreactive peptides are degraded more effectively when digestive enzymes are supported by the addition of PEP. © 2017 Society of Chemical Industry.

Effectiveness of Germination on Protein Hydrolysis as a Way To Reduce Adverse Reactions to Wheat

In this work, the aim is to study the effectiveness of germination on wheat protein degradation, with a specific focus on proteins involved in adverse reactions to wheat. The effects of 8 days of germination at 25 °C on the chemical composition and the protein profile were determined. Germination did not have a significant effect on starch, protein, lipid, and ash contents. General protein profile, as indicated by SDS-PAGE analysis, revealed that germination induced a relevant degradation in protein fraction. After in vitro gastrointestinal digestion, gluten peptides involved in celiac disease (CD) were identified and quantified using UPLC/ESI-MS technique. Also, CM3 protein, involved in baker's asthma and intestinal inflammation, was quantified by measuring a marker peptide. Statistical analysis underlined that germination and genotype had significant impact on the amount of both components. Regarding gluten peptides related to CD, germination enabled an average reduction of 47% in peptides eliciting adaptive immune response and 46% in peptides eliciting innate immune response. CM3 protein showed also a high average reduction (56%). Thus, this study suggests that germination might be a good bioalternative to provide a low "impact" raw ingredient for special wheat-based foodstuffs.

Effects of enzyme activities during steeping and sprouting on the solubility and composition of proteins, their bioactivity and relationship with the bread making quality of wheat flour

The aim was to determine the effect of steeping and sprouting on wheat grain proteins and the functional consequences in this regard.