Possibility of minimizing gluten intolerance by co-consumption of some fruits – A case for positive food synergy?

Bromelain-loaded nanocomposites decrease inflammatory and cytotoxicity effects of gliadin on Caco-2 cells and peripheral blood mononuclear cells of celiac patients

Enzyme therapy can be an appropriate treatment option for celiac disease (CeD). Here, we developed Bromelain-Loaded Nanocomposites (BLNCs) to improve the stability and retention of bromelain enzyme activity. After the characterization of BLNCs, the cytotoxicity of BLNCs was determined on the Caco-2 cell line. The effect of BLNCs on gliadin degradation and the production of pro-inflammatory cytokines and anti-inflammatory molecules in peripheral blood mononuclear cells (PBMCs) obtained from celiac patients were assessed. Furthermore, the expression of CXCR3 and CCR5 genes was measured in CaCo-2 cells treated with gliadin, gliadin-digested with BLNCs, and bromelain. Our study demonstrated that the Bromelain entrapment efficiency in these nanoparticles was acceptable, and BLNCs have no toxic effect on cells. SDS-PAGE confirmed the digestion effect of bromelain released from nanocomposites. When Caco-2 cells were treated with gliadin digested by free bromelain and BLNCs, the expression of CXCR3 and CCR5 genes was significantly decreased. PBMCs of celiac patients treated with Bromelain and BLNCs decreased inflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ) production compared to untreated PBMCs. This treatment also increased IL-10 and CTLA-4 in PBMCs of CeD patients. According to the promising results of this study, we can hope for the therapeutic potential of BLNCs for CeD.

Bromelain and ficin proteolytic effects on gliadin cytotoxicity and expression of genes involved in cell-tight junctions in Caco-2 cells

Enzyme therapy for celiac disease (CeD), which digests gliadin into non-immunogenic and non-toxic peptides, can be an appropriate treatment option for CeD. Here, we have investigated the effectiveness of bromelain and ficin on gliadin digestion using in vitro, such as SDS-PAGE, HPLC, and circular dichroism (CD). Furthermore, the cytotoxicity of gliadin and 19-mer peptide before and after digestion with these enzymes was evaluated using the MTT assay in the Caco-2 cell line. Finally, we examined the effect of these treatments along with Larazotide Acetate on the expression of genes involved in cell-tight junctions, such as Occludin, Claudin 3, tight junction protein-1, and Zonulin in the Caco-2 cell line. Our study demonstrated bromelain and ficin digestion effects on the commercial and wheat-extracted gliadin by SDS-PAGE, HPLC, and CD. Also, the cytotoxicity results on Caco-2 showed that toxicity of the gliadin and synthetic 19-mer peptide was decreased by adding bromelain and ficin. Furthermore, the proteolytic effects of bromelain and ficin on gliadin indicated the expression of genes involved in cell-tight junctions was improved. This study confirms that bromelain and ficin mixture could be effective in improving the symptoms of CeD.

Understanding the Molecular Basis for Enhanced Glutenase Activity of Actinidin using Structural Bioinformatics

BACKGROUND

Management of gluten intolerance is currently possible only by consumption of a gluten-free diet (GFD) for a lifetime. The scientific community has been searching for alternatives to GFD, like the inclusion of natural proteases with meals or pre-treatment of gluten-containing foods with glutenases. Actinidin from kiwifruit has shown considerable promise in digesting immunogenic gliadin peptides compared to other plant-derived cysteine proteases.

METHODS

In this study, we aimed to understand the structural basis for the elevated protease action of actinidin against gliadin peptides by using an in silico approach.

RESULTS

Docking experiments revealed key differences between the binding of gliadin peptide to actinidin and papain, which may be responsible for their differential digestive action.

CONCLUSION

Sequence comparison of different plant cysteine proteases highlights amino acid residues surrounding the active site pocket of actinidin that are unique to this molecule and hence likely to contribute to its digestive properties.

The Efficacy of Plant Enzymes Bromelain and Papain as a Tool for Reducing Gluten Immunogenicity from Wheat Bran

Gluten-free products made from naturally gluten-free raw materials have an inferior taste and can cause deficiencies in various nutrients, especially non-starch polysaccharides. To address this problem, scientists are searching for new strategies to eliminate harmful gluten from wheat, rye, and barley and to produce balanced products with good organoleptic properties. This study evaluated the possibility of hydrolysing gluten in wheat bran, a by-product obtained after the dry fractionation of wheat, using plant enzymes. The gluten content of wheat bran after treatment with papain, bromelain, and their combination under different hydrolysis conditions was investigated. The amount of gluten was determined using an enzyme-linked immunosorbent assay ELISA R5 and the reduction in immunogenic gliadins was analysed using high-performance reverse phase liquid chromatography. The results of the study showed that 4 h hydrolysis with bromelain and papain reduced the levels of gluten immunogenic compounds in bran from 58,650.00 to 2588.20–3544.50 mg/kg; however, they did not reach the gluten-free limit. A higher hydrolysis efficiency of 95.59% was observed after treatment with papain, while the combination of both enzymes and bromelain alone were less effective. The results presented in this article will be helpful to other researchers and manufacturers of wheat-based products when selecting methods to reduce gluten immunogenicity and contribute to the development of sustainable technologies.

Rapid proteolysis of gluten-derived immunogenic peptides in bread by actinidin in a combined in vivo and in vitro oro-gastrointestinal digestion model

This study aimed to determine the ability of actinidin, a cysteine protease in green kiwifruit (Actinidia deliciosa), to hydrolyse wheat proteins and gluten-derived immunogenic peptides from a commonly consumed food matrix (bread) using a combined in vivo and in vitro oro-gastrointestinal tract (GIT) model. A chewed and spat composite bolus of bread was in vitro digested with or without purified actinidin using a human gastric simulator (HGS). Gastric digestion was conducted for 150 min with gastric emptying occurring at different time points. Emptied samples were immediately digested under simulated small intestinal conditions. Gastric and small intestinal aliquots were collected to quantify peptide profiles and nine marker immunogenic peptides (by untargeted and targeted mass spectrometry, respectively), R5 epitopes (by monoclonal antibody-based competition assay), and free amino groups released by digestion (by the o-phthaldialdehyde method). There was a significant effect (P < 0.05) of actinidin and digestion time on the hydrolysis of wheat proteins and the amount of gluten R5 epitopes of that material emptying the HGS. Actinidin accelerated 1.2-fold the gastric hydrolysis of wheat proteins during the first 20 min of digestion, which was reflected in a faster (5.5 μg min^-1) reduction in the evolution of R5 epitopes. Actinidin accelerated (P < 0.05) the rate of disappearance of most of the immunogenic marker peptides. For example, in the first 20 min of small intestinal digestion, the 33-mer peptide decreased (P < 0.05) 2-fold faster (0.25 vs. 0.12 μg g^-1 of bread per min) in the presence of actinidin than in the control. Untargeted peptidomics showed actinidin decreased the amounts of known immunogenic peptides in the simulated small intestinal digestion. These findings demonstrated that actinidin accelerates the hydrolysis of wheat proteins and known gluten immunogenic peptides in a commonly consumed food matrix (bread) in a combined in vivo and in vitro oro-GIT digestion model.

New alternatives from sustainable sources to wheat in bakery foods: Science, technology, and challenges

Ongoing research in the food industry is striving to replace wheat flour with new alternatives from sustainable sources to overcome the disease burden in the existing population. Celiac disease, wheat allergy, gluten sensitivity, or non-celiac gluten sensitivity are some common disorders associated with gluten present in wheat. These scientific findings are crucial to finding appropriate alternatives in introducing new ingredients supporting the consumer's requirements. Among the alternatives, amaranth, barley, coconut, chestnut, maize, millet, teff, oat, rye, sorghum, soy, rice flour, and legumes could be considered appropriate due to their chemical composition, bioactive profile, and alternatives utilization in the baking industry. Furthermore, the enrichment of these alternatives with proper ingredients is considered effective. Literature demonstrated that the flours from these alternative sources significantly enhanced the physicochemical, pasting, and rheological properties of the doughs. These flours boost a significant reduction in gluten proteins associated with food intolerance, in comparison with wheat highlighting a visible market opportunity with nutritional and organoleptic benefits for food producers. PRACTICAL APPLICATIONS: New alternatives from sustainable sources to wheat in bakery foods as an approach that affects human health. Alternatives from sustainable sources are important source of nutrients and bioactive compounds. Alternatives from sustainable sources are rising due to nutritional and consumer demand in bakery industry. New alternatives from sustainable sources improve physicochemical, pasting, and rheological properties of dough. Non-wheat-based foods from non-traditional grains have a potential to increase consumer market acceptance.

Production of Plant Proteases and New Biotechnological Applications: An Updated Review

An updated review of emerging plant proteases with potential biotechnological application is presented. Plant proteases show comparable or even greater performance than animal or microbial proteases for by-product valorization through hydrolysis for, for example, cheese whey, bird feathers, collagen, keratinous materials, gelatin, fish protein, and soy protein. Active biopeptides can be obtained as high added value products, which have shown numerous beneficial effects on human health. Plant proteases can also be used for wastewater treatment. The production of new plant proteases is encouraged for the following advantages: low cost of isolation using simple procedures, remarkable stability over a wide range of operating conditions (temperature, pH, salinity, and organic solvents), substantial affinity to a broad variety of substrates, and possibility of immobilization. Vegetable proteases have enormous application potential for the valorization of industrial waste and its conversion into products with high added value through low-cost processes.

The kiwifruit enzyme actinidin enhances the hydrolysis of gluten proteins during simulated gastrointestinal digestion

This study investigated the effect of actinidin, a cysteine protease in kiwifruit, on the hydrolysis of gluten proteins and digestion-resistant gluten peptides (synthetic 33-mer peptide and pentapeptide epitopes) under static simulated gastrointestinal conditions. Actinidin efficacy in hydrolysing gliadin was compared with that of other gluten-degrading enzymes. Actinidin hydrolysed usually resistant peptide bonds adjacent to proline residues in the 33-mer peptide. The gastric degree of hydrolysis of gluten proteins was influenced by an interaction between pH and actinidin concentration (P < 0.05), whereas the pentapeptide epitopes hydrolysis was influenced only by the actinidin concentration (P < 0.05). The rate of gastric degree of hydrolysis of gliadin was greater (P < 0.05) by actinidin (0.8%/min) when compared to papain, bromelain, and one commercial enzyme (on average 0.4%/min), while all exogenous enzymes were able to hydrolyse the pentapeptide epitopes effectively. Actinidin is able to hydrolyse gluten proteins under simulated gastric conditions.