Use of selected sourdough lactic acid bacteria to hydrolyze wheat and rye proteins responsible for cereal allergy

Study on the reduction of Tartary buckwheat allergenicity during Pediococcus pentosaceus fermentation by HPLC-MS/MS analysis

Tartary buckwheat contains more valuable nutrients than common buckwheat, but it also contains allergenic proteins that induce allergic reactions through an IgE-mediated response. Our study demonstrated that fermentation by Pediococcus pentosaceus degrades allergenic proteins in Tartary buckwheat, as confirmed by HPLC-MS/MS analysis of polypeptides. Our results showed significant degradation of the protein after 16 h of Pediococcus pentosaceus fermentation (PP16), leading to a reduction in IgE-binding activity. Comparison with unfermented Tartary buckwheat (UTB) peptides yielded 2042 fragments, of which 756 fragments associated with allergenic proteins were upregulated. Among them, the expression of 213 fragments was reduced by 71.83%. By performing bioactivity prediction on potential allergenic peptide fragments, we identified six peptide fragments derived from Fagt 1, potentially contributing to the residual allergenicity in PP16. These suggest that Pediococcus pentosaceus fermentation can effectively destroy allergen epitopes and mitigate the allergenicity of Tartary buckwheat.

Tackling food allergens-The role of food processing on proteins' allergenicity

This chapter examines how innovative and emerging food processing technologies, such as those that use heat, electricity, electromagnetic waves, and pressure, can modify protein denaturation, aggregation, and intermolecular interactions pathways, which can result in varying immunoreactive responses. It emphasizes the need to understand how these processing methods affect the protein epitopes recognized by antibodies and their respective priming pathways, especially during the sensitization stage that precedes an allergic response. Although traditional processing methods have been investigated, the impact of novel technologies on food protein allergenicity remains largely unknown. The chapter specifically focuses on milk proteins, which have clinical significance and are associated with cow's milk allergy, one of the most common food allergies in young children. Additionally, it examines potential scientific advancements that novel processing methods may bring to this field.

Significance of Fermentation in Plant-Based Meat Analogs: A Critical Review of Nutrition, and Safety-Related Aspects

Plant-based meat analogs have been shown to cause less harm for both human health and the environment compared to real meat, especially processed meat. However, the intense pressure to enhance the sensory qualities of plant-based meat alternatives has caused their nutritional and safety aspects to be overlooked. This paper reviews our current understanding of the nutrition and safety behind plant-based meat alternatives, proposing fermentation as a potential way of overcoming limitations in these aspects. Plant protein blends, fortification, and preservatives have been the main methods for enhancing the nutritional content and stability of plant-based meat alternatives, but concerns that include safety, nutrient deficiencies, low digestibility, high allergenicity, and high costs have been raised in their use. Fermentation with microorganisms such as Bacillus subtilis, Lactiplantibacillus plantarum, Neurospora intermedia, and Rhizopus oryzae improves digestibility and reduces allergenicity and antinutritive factors more effectively. At the same time, microbial metabolites can boost the final product's safety, nutrition, and sensory quality, although some concerns regarding their toxicity remain. Designing a single starter culture or microbial consortium for plant-based meat alternatives can be a novel solution for advancing the health benefits of the final product while still fulfilling the demands of an expanding and sustainable economy.

Gluten-Free Bread Enriched with Artichoke Leaf Extract In Vitro Exerted Antioxidant and Anti-Inflammatory Properties

Due to its high nutritional value and broad beneficial effects, the artichoke plant (Cynara cardunculus L.) is an excellent healthy food candidate. Additionally, the artichoke by-products are usually discarded even though they still contain a huge concentration of dietary fibers, phenolic acids, and other micronutrients. The present work aimed to characterize a laboratory-made gluten-free bread (B) using rice flour supplemented with a powdered extract from artichoke leaves (AEs). The AE, accounting for the 5% of titratable chlorogenic acid, was added to the experimental gluten-free bread. Accounting for different combinations, four different bread batches were prepared. To evaluate the differences, a gluten-free type-II sourdough (tII-SD) was added in two doughs (SB and SB-AE), while the related controls (YB and YB-AE) did not contain the tII-SD. Profiling the digested bread samples, SB showed the lowest glycemic index, while SB-AE showed the highest antioxidant properties. The digested samples were also fermented in fecal batches containing viable cells from fecal microbiota samples obtained from healthy donors. Based on plate counts, no clear tendencies emerged concerning the analyzed microbial patterns; by contrast, when profiling volatile organic compounds, significant differences were observed in SB-AE, exhibiting the highest scores of hydrocinnamic and cyclohexanecarboxylic acids. The fecal fermented supernatants were recovered and assayed for healthy properties on human keratinocyte cell lines against oxidative stress and for effectiveness in modulating the expression of proinflammatory cytokines in Caco-2 cells. While the first assay emphasized the contribution of AE to protect against stressor agents, the latter enlightened how the combination of SB with AE decreased the cellular TNF-α and IL1-β expression. In conclusion, this preliminary study suggests that the combination of AE with sourdough biotechnology could be a promising tool to increase the nutritional and healthy features of gluten-free bread.

Research Progress on the Correlation between the Intestinal Microbiota and Food Allergy

The increasing incidence of food allergy is becoming a substantial public health concern. Increasing evidence suggests that alterations in the composition of the intestinal microbiota play a part in the development of food allergy. Additionally, the application of probiotics to correct gut microbiota imbalances and regulate food allergy has become a research hotspot. However, the mechanism by which the gut microbiota regulates food allergy and the efficacy of probiotics are still in the preliminary exploration stage, and there are no clear and specific conclusions. The aim of this review is to provide information regarding the immune mechanism underlying food allergy, the correlation between the intestinal microbiota and food allergy, a detailed description of causation, and mechanisms by which the intestinal microbiota regulates food allergy. Subsequently, we highlight how probiotics modulate the gut microbiome–immune axis to alleviate food allergy. This study will contribute to the dovetailing of bacterial therapeutics with immune system in allergic individuals to prevent food allergy and ameliorate food allergy symptoms.

Consumption of Yeast-Fermented Wheat and Rye Breads Increases Colitis and Mortality in a Mouse Model of Colitis

BACKGROUND

Cereals are known to trigger for wheat allergy, celiac disease and non-celiac wheat sensitivity (NCWS). Inflammatory processes and intestinal barrier impairment are suspected to be involved in NCWS, although the molecular triggers are unclear.

AIMS

We were interested if different bread types influence inflammatory processes and intestinal barrier function in a mouse model of inflammatory bowel disease.

METHODS

Epithelial caspase-8 gene knockout (Casp8ΔIEC) and control (Casp8fl) mice were randomized to eight groups, respectively. The groups received different diets for 28 days (gluten-free diet, gluten-rich diet 5 g%, or different types of bread at 50 g%). Breads varied regarding grain, milling and fermentation. All diets were isocaloric.

RESULTS

Regardless of the diet, Casp8ΔIEC mice showed pronounced inflammation in colon compared to ileum, whereas Casp8fl mice were hardly inflamed. Casp8fl mice could tolerate all bread types. Especially yeast fermented rye and wheat bread from superfine flour but not pure gluten challenge increased colitis and mortality in Casp8ΔIEC mice. Hepatic expression of lipopolysaccharide-binding protein and colonic expression of tumor necrosis factor-α genes were inversely related to survival. The bread diets, but not the gluten-rich diet, also decreased colonic tight junction expression to variable degrees, without clear association to survival and inflammation.

CONCLUSIONS

Bread components, especially those from yeast-fermented breads from wheat and rye, increase colitis and mortality in Casp8ΔIEC mice highly susceptible to intestinal inflammation, whereas control mice can tolerate all types of bread without inflammation. Yet unidentified bread components other than gluten seem to play the major role.

Comprehensive proteome analysis of bread deciphering the allergenic potential of bread wheat, spelt and rye

BACKGROUND/OBJECTIVES

Cereal products like flour and bread are known to trigger diseases such as wheat allergy, celiac disease and non-celiac wheat sensitivity (NCWS). Some of these diseases are caused by allergenic proteins, the expression of which might vary depending on the grain type and manufacturing processes. Therefore, we examined the protein composition and abundance of potentially allergenic proteins in flours from bread wheat, spelt and rye, and corresponding breads.

MATERIALS AND METHODS

Using Nano-LC-ESI-MS/MS and label free quantification (LFQ) we analyzed the proteome of six different bread flours (wholegrain and superfine flours from rye, spelt and bread wheat) and 14 bread types (yeast and sourdough fermented breads from all flours and wheat breads plus/minus bread improver). Potentially allergenic proteins in flours and breads were functionally categorized using the Pfam database and relatively quantified by LFQ.

RESULTS

We could show that almost equal numbers of proteins can be identified in rye- and spelt samples compared to wheat samples using the Uniprot bread wheat protein database, indicating high sequence conservation between cereals. In total, 4424 proteins were identified in the 20 flour and bread samples. The average number of identified proteins in flour (2719 ± 243) was slightly higher than in bread (2283 ± 232; P < 0.001). In wheat- and spelt wholegrain flour higher protein numbers (wheat: 2891 ± 90; spelt: 2743 ± 140) were identified on average than in superfine flour (wheat: 2562 ± 79; P = 0.009; spelt: 2431 ± 140; P = 0.004). Neither the absolute number nor the abundance distribution of potentially allergenic proteins were dependent on the flour type or the fermentation process, but known allergenic proteins like gliadins showed higher relative abundance in spelt- and wheat samples, compared to rye samples.

CONCLUSION

We provide comprehensive proteome data for six flour types and related breads showing that the grain species have greater influence on proteome composition than milling and fermentation processes. Our data indicate that allergenic proteins are not selectively degraded during bread production and are more abundant in bread wheat and spelt compared to rye.

SIGNIFICANCE

Our proteomics study revealed that bread contains a number of potentially and proven allergenic proteins. Most likely allergenicity is not dependent on milling or conventional fermentation processes, but on the grain type. Relative abundance of allergenic proteins was higher in spelt- and wheat samples than in rye samples. Considering rye bread as better suited to atopic individuals predisposed to react to cereal allergens, clinical trials are warranted to verify this assumption.

Fermentation of Gluten by Lactococcus lactis LLGKC18 Reduces its Antigenicity and Allergenicity

Wheat is a worldwide staple food, yet some people suffer from strong immunological reactions after ingesting wheat-based products. Lactic acid bacteria (LAB) constitute a promising approach to reduce wheat allergenicity because of their proteolytic system. In this study, 172 LAB strains were screened for their proteolytic activity on gluten proteins and α-amylase inhibitors (ATIs) by SDS-PAGE and RP-HPLC. Gliadins, glutenins, and ATI antigenicity and allergenicity were assessed by Western blot/Dot blot and by degranulation assay using RBL-SX38 cells. The screening resulted in selecting 9 high gluten proteolytic strains belonging to two species: Enterococcus faecalis and Lactococcus lactis. Proteomic analysis showed that one of selected strains, Lc. lactis LLGKC18, caused degradation of the main gluten allergenic proteins. A significant decrease of the gliadins, glutenins, and ATI antigenicity was observed after fermentation of gluten by Lc. lactis LLGKC18, regardless the antibody used in the tests. Also, the allergenicity as measured by the RBL-SX38 cell degranulation test was significantly reduced. These results indicate that Lc. lactis LLGKC18 gluten fermentation can be deeply explored for its capability to hydrolyze the epitopes responsible for wheat allergy.

Recent advances in alleviating food allergenicity through fermentation

The increasing prevalence of food allergies is a significant challenge to global food health and safety. Various strategies have been deployed to decrease the allergenicity of food for preventing and reducing related disorders. Compared to other methods, fermentation has unique advantages in reducing the allergenicity of food and may represent a new trend in preventing food-induced allergies. This review introduces the characteristics of allergens in various foods, including shellfish, soy, peanut, milk, tree nut, egg, wheat, and fish. The mechanism and pathological symptoms of allergic reactions are then summarized. Furthermore, the advantages of fermentation for reducing the allergenicity of these foods and preventing allergies are evaluated. Fermentation is an efficient approach for reducing or eliminating food allergenicity. Simultaneously, it improved the nutritional value and physicochemical properties of food materials. It is conceivable that a combination of mixed strain fermentation with additional processing, such as heat treatment, pulsed light, and ultrasonication, will efficiently reduce the allergenicity of various foods and preserve their unique taste and nutritional components, providing significance for patients with allergies.

Allergenicity of Fermented Foods: Emphasis on Seeds Protein-Based Products

Food allergy is an IgE-mediated abnormal response to otherwise harmless food proteins, affecting between 5% and 10% of the world preschool children population and 1% to 5% adults. Several physical, chemical, and biotechnological approaches have been used to reduce the allergenicity of food allergens. Fermentation processes that contribute to technological and desirable changes in taste, flavor, digestibility, and texture of food products constitute one of these approaches. Lactic acid bacteria (LAB), used as starter cultures in dairy products, are a subject of increasing interest in fermentation of plant proteins. However, the studies designed to assess the impact of LAB on reduction of allergenicity of seed proteins are at an early stage. This review presents the current knowledge on food fermentation, with a focus on seed proteins that are increasingly used as ingredients, and its impacts on food potential allergenicity.

Biliaderis C. Fermented Cereal-based Products: Nutritional Aspects, Possible Impact on Gut Microbiota and Health Implications

Fermentation, as a process to increase the security of food supply, represents an integral part of food culture development worldwide. Nowadays, in the evolving functional food era where new sophisticated technological tools are leading to significant transformations in the field of nutritional sciences and science-driven approaches for new product design, fermentation technology is brought to the forefront again since it provides a solid foundation for the development of safe food products with unique nutritional and functional attributes. Therefore, the objective of the present review is to summarize the most recent advances in the field of fermentation processes related to cereal-based products. More specifically, this paper addresses issues that are relevant to nutritional and health aspects, including their interrelation with intestinal (gut) microbiome diversity and function, although clinical trials and/or in vitro studies testing for cereal-based fermented products are still scarce.

The Inhibition of Amylase and ACE Enzyme and the Reduction of Immunoreactivity of Sourdough Bread

This study examines the potential health benefits of different types of wheat sourdough bread against diseases of civilization. Celiac disease, diabetes and hypertension affect large numbers of the world's population, increasing demand for novel treatments and ways of improving patient welfare. Different types of artisan breads were subjected to in vitro simulated digestion prior to analysis. The G12 test and ELISA with human sera were used for immunoreactivity analysis. The activity of α-amylase inhibitors and angiotensin-converting enzymes (ACE) was also assessed. The addition of sourdough to the analyzed wheat bread raised the content of α-amylase inhibitors and angiotensin-converting enzyme inhibitors while reducing their immunoreactivity. However, despite decreases in the antigenicity of the wheat flour proteins, the sera showed various reactions, depending on the individual patient's susceptibility to gluten.

Fermentation for tailoring the technological and health related functionality of food products

Fermented foods are experiencing a resurgence due to the consumers' growing interest in foods that are natural and health promoting. Microbial fermentation is a biotechnological process which transforms food raw materials into palatable, nutritious and healthy food products. Fermentation imparts unique aroma, flavor and texture to food, improves digestibility, degrades anti-nutritional factors, toxins and allergens, converts phytochemicals such as polyphenols into more bioactive and bioavailable forms, and enriches the nutritional quality of food. Fermentation also modifies the physical functional properties of food materials, rendering them differentiated ingredients for use in formulated foods. The science of fermentation and the technological and health functionality of fermented foods is reviewed considering the growing interest worldwide in fermented foods and beverages and the huge potential of the technology for reducing food loss and improving nutritional food security.

Stability of allergens

For proteins to cause IgE-mediated allergic reactions, several common characteristics have to be defined, including small molecular size, solubility and stability to changing pH levels and enzymatic degradation. Nevertheless, these features are not unique for potent allergens, but are also observed in non-allergenic proteins. Due to the increasing awareness by regulatory authorities regarding the allergy pandemic, definition of characteristics unique to potent allergens would facilitate allergenicity assessment in the future. Despite major research efforts even to date the features unique for major allergens have not been elucidated so far. The route of allergen entry into the organism determines to a great extent these required characteristics. Especially orally ingested allergens are exposed to the harsh milieu of the gastrointestinal tract but might additionally be influenced by food processing. Depending on molecular properties such as disulphide bonds contributing to protein fold and formation of conformational IgE epitopes, posttranslational protein modification or protein food matrix interactions, enzymatic and thermal stability might differ between allergens. Moreover, also ligand binding influences structural stability. In the current review article, we aim at highlighting specific characteristics and molecular pattern contributing to a stabilized protein structure and overall allergenicity.

Effects of water stress on the composition and immunoreactive properties of gliadins from two wheat cultivars: Nawra and Tonacja

BACKGROUND

Water shortage during wheat vegetation causes changes in the composition of gliadins in grains, which can lead to changes in their immunoreactive properties.

RESULTS

The investigated wheat cultivars exposed to water stress accumulated significantly lower amounts (P < 0.05) of gliadins and glutenins in grains. The composition of proteins accumulated in grains was also modified. Water shortage results in a decreased share of αβ and γ fractions in total gliadins. Grains of wheat cultivated under water stress contain significantly higher (P < 0.05) levels of ω-gliadins by 4.5% and 43.3% for Nawra and Tonacja cultivars, respectively. Water stress promotes an increase in the share of P and Q/E residues in gliadins. In protein samples R5 antibodies recognized increased amounts of gliadins matching the QQPFP sequence. Wheat proteins also reacted with IgE antibodies isolated from subjects allergic to gluten.

CONCLUSION

Cultivation of wheat under conditions of water stress results in the qualitative and quantitative changes of gliadins by increasing their immunoreactivity. © 2016 Society of Chemical Industry.

Selection of lactic acid bacteria strains for the hydrolysis of allergenic proteins of wheat flour

BACKGROUND

Wheat flour is one of the most common causative agents of food allergy. The study presents the selection and characterization of lactic acid bacteria (LAB) strains capable of hydrolyzing/modifying allergenic proteins of wheat flour. Hydrolysis of wheat proteins was determined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with sera from patients with food allergy to gluten.

RESULTS

The analysis of electrophoretic profiles of protein extracted from sourdough shows the capability of selected LAB strains for proteolytic degradation of wheat proteins that belong to two factions: albumin/globulin (hydrolysis of 13 polypeptides with a molecular weight between 103 and 22 kDa); and gliadin (seven polypeptides with a molecular weight between 39 and 24 kDa). All analyzed strains were capable of hydrolyzing some IgE-binding epitopes of wheat allergens. The lack of such changes in control samples indicates that they were induced rather by the proteolytic activity of bacterial strains than endogenous enzymes of wheat flour. The gluten proteins were susceptible to hydrolysis by sequential digestion with pepsin and trypsin.

CONCLUSION

The selected strains exhibit proteolytic activity, which leads to a reduction in allergenicity of wheat sourdoughs. These strains may be applied as specific starter cultures to prepare bakery products of special nutritional use. © 2015 Society of Chemical Industry.

Food processing and allergenicity

Food processing can have many beneficial effects. However, processing may also alter the allergenic properties of food proteins. A wide variety of processing methods is available and their use depends largely on the food to be processed. In this review the impact of processing (heat and non-heat treatment) on the allergenic potential of proteins, and on the antigenic (IgG-binding) and allergenic (IgE-binding) properties of proteins has been considered. A variety of allergenic foods (peanuts, tree nuts, cows' milk, hens' eggs, soy, wheat and mustard) have been reviewed. The overall conclusion drawn is that processing does not completely abolish the allergenic potential of allergens. Currently, only fermentation and hydrolysis may have potential to reduce allergenicity to such an extent that symptoms will not be elicited, while other methods might be promising but need more data. Literature on the effect of processing on allergenic potential and the ability to induce sensitisation is scarce. This is an important issue since processing may impact on the ability of proteins to cause the acquisition of allergic sensitisation, and the subject should be a focus of future research. Also, there remains a need to develop robust and integrated methods for the risk assessment of food allergenicity.

How the sourdough may affect the functional features of leavened baked goods

Sourdough fermentation is one of the oldest food biotechnologies, which has been studied and recently rediscovered for its effect on the sensory, structural, nutritional and shelf life properties of leavened baked goods. Acidification, proteolysis and activation of a number of enzymes as well as the synthesis of microbial metabolites cause several changes during sourdough fermentation, which affect the dough and baked good matrix, and influence the nutritional/functional quality. Currently, the literature is particularly rich of results, which show how the sourdough fermentation may affect the functional features of leavened baked goods. In the form of pre-treating raw materials, fermentation through sourdough may stabilize or to increase the functional value of bran fractions and wheat germ. Sourdough fermentation may decrease the glycaemic response of baked goods, improve the properties and bioavailability of dietary fibre complex and phytochemicals, and may increase the uptake of minerals. Microbial metabolism during sourdough fermentation may also produce new nutritionally active compounds, such as peptides and amino acid derivatives (e.g., γ-amino butyric acid) with various functionalities, and potentially prebiotic exo-polysaccharides. The wheat flour digested via fungal proteases and selected sourdough lactobacilli has been demonstrated to be probably safe for celiac patients.

Proteomic analysis in allergy and intolerance to wheat products

Owing to its extensive use in the human diet, wheat is among the most common causes of food-related allergies and intolerances. Allergies to wheat are provoked by ingestion, inhalation or contact with either the soluble or the insoluble gluten proteins in wheat. Gluten proteins, and particularly the gliadin fraction, are also the main factor triggering celiac disease, a common enteropathy induced by ingestion of wheat gluten proteins and related prolamins from oat, rye and barley in genetically susceptible individuals. The role of gliadin and of its derived peptides in eliciting the adverse reactions in celiac disease are still far from being completely explained. Owing to its unique pathogenesis, celiac disease is widely investigated as a model immunogenetic disorder. The structural characterization of the injuring agents, the gluten proteins, assumes a particular significance in order to deepen the understanding of the events that trigger this and similar diseases at the molecular level. Recent developments in proteomics have provided an important contribution to the understanding of several basic aspects of wheat protein-related diseases. These include: the identification of gluten fractions and derived peptides involved in wheat allergy and intolerance, including celiac disease, and the elucidation of their mechanism of toxicity; the development and validation of sensitive and specific methods for detecting trace amounts of gluten proteins in gluten-free foods for intolerant patients; and the formulation of completely new substitute foods and ingredients to replace the gluten-based ones. In this article, the main aspects of current and prospective applications of mass spectrometry and proteomic technologies to the structural characterization of gluten proteins and derived peptides are critically presented, with a focus on issues related to their detection, identification and quantification, which are relevant to the biochemical, immunological and toxicological aspects of wheat intolerance.

Functional microorganisms for functional food quality

Functional microorganisms and health benefits represent a binomial with great potential for fermented functional foods. The health benefits of fermented functional foods are expressed either directly through the interactions of ingested live microorganisms with the host (probiotic effect) or indirectly as the result of the ingestion of microbial metabolites synthesized during fermentation (biogenic effect). Since the importance of high viability for probiotic effect, two major options are currently pursued for improving it--to enhance bacterial stress response and to use alternative products for incorporating probiotics (e.g., ice cream, cheeses, cereals, fruit juices, vegetables, and soy beans). Further, it seems that quorum sensing signal molecules released by probiotics may interact with human epithelial cells from intestine thus modulating several physiological functions. Under optimal processing conditions, functional microorganisms contribute to food functionality through their enzyme portfolio and the release of metabolites. Overproduction of free amino acids and vitamins are two classical examples. Besides, bioactive compounds (e.g., peptides, γ-amino butyric acid, and conjugated linoleic acid) may be released during food processing above the physiological threshold and they may exert various in vivo health benefits. Functional microorganisms are even more used in novel strategies for decreasing phenomenon of food intolerance (e.g., gluten intolerance) and allergy. By a critical approach, this review will aim at showing the potential of functional microorganisms for the quality of functional foods.

Two-dimensional electrophoresis and IgE-mediated food allergy

Food allergy is recognized as one of the major health concerns. It is estimated that ca. 4% of the population is affected by food allergenic disorders. Food allergies are defined as IgE-mediated hypersensitivity reactions. Foods such as peanuts, tree nuts, wheat, soy, cow's milk, egg, fish and shellfish are regarded as responsible for the majority of reactions. The ubiquitous presence of allergens in the human foods coupled with an increased awareness of food allergies warrants to undertake appropriate preventive measures for protecting sensitive consumers from unwanted exposure to offending food allergens. 2-DE followed by immunoblotting and identification of IgE-reactive proteins, as a proteomic approach to identify new allergens in foods, are reviewed. Specific examples of identification of allergens in foods and beverages by using 2-DE and IgE are described. Protein profiling using 2-DE and allergens detection by IgE has become a powerful method for analyzing changes of allergens content in complex matrix during food processing.

Effects of fermentation by lactic acid bacteria on the antigenicity of bovine whey proteins

BACKGROUND

The main whey proteins alpha-lactalbumin (alpha-LA) and beta-lactoglobulin (beta-LG) are considered as the major allergens in cow's milk. Microbial fermentation can produce some proteolytic enzymes, which can induce the degradation of milk protein allergens. In this study, the effects of fermentation by lactic acid bacteria on the antigenicity of alpha-LA and beta-LG were investigated using indirect competitive ELISA. Meanwhile, the proteolysis of milk proteins was detected by TNBS assay and SDS-PAGE electrophoresis.

RESULTS

Fermentation by lactic acid bacteria could significantly reduce the antigenicity of alpha-LA and beta-LG in skim milk. Combined strains of Lactobacillus helveticus and Streptococcus thermophilus were the most effective in reducing the antigenicity of both whey proteins. In addition, alpha-LA and beta-LG antigenicity decreased to a lower value at 6 h of fermentation and at 0.5 d of cold storage by fermentation with the combined strains. The results of TNBS assay and SDS-PAGE electrophoresis showed that lactic acid bacteria strains used in this study hydrolysed whey proteins only to a limited extent.

CONCLUSION

The fermentation with lactic acid bacteria is an effective way to reduce whey proteins antigenicity.

Use of selected enterococci and Rhizopus oryzae proteases to hydrolyse wheat proteins responsible for celiac disease

AIMS

This work aimed at using a pool of selected enterococci and fungal proteases to hydrolyse wheat gluten during long-time fermentation.

METHODS AND RESULTS

A liquid dough made with wheat flour (20% w/w) was fermented with three Enterococcus strains (dough A) or with the combination of enterococci and Rhizopus oryzae proteases (dough B). After 48 h of fermentation, dough A and B had a concentration of water-soluble peptides approximately threefold higher than the chemically acidified dough (CAD), used as the control. The same was found for the concentration of free amino acids, being higher in dough B with respect to dough A. SDS-PAGE analysis showed that albumin and glutenin fractions were partially hydrolysed, while gliadins almost disappeared in dough A and B, as confirmed by two-dimensional electrophoresis, RP-HPLC and R5-ELISA analyses.

CONCLUSIONS

The combined use of enterococci and fungal proteases showed a decrease of the gluten concentration of more than 98% during long-time fermentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of the mixture of selected enterococci and R. oryzae proteases should be considered as a potential tool to decrease gluten concentration in foods.