Reinventing the nutraceutical value of gluten: The case of l-theanine-gluten as a potential alternative to the gluten exclusion diet in celiac disease

Detoxification Mechanism and the Impact of Transamidation-Modified Gliadin on Celiac-Based Gluten Sensitivity: The Potential of Unlocking Gluten Tolerance in Functional Food

Transamidation of gliadin under reducing conditions has shown promise in mitigating celiac disease-related gluten toxicity. However, comprehensive evaluation in both in vitro and in vivo models is crucial. This study investigated the effects of transamidated gliadin (GM) on celiac toxicity using Caco-2 cell monolayers, bone marrow-derived dendritic cells (BMDCs), and a BALB/c mouse model. In cellular level, GM mitigated intestinal damage compared to unmodified gliadin and stimulated a less pronounced pro-inflammatory response, suggesting a reduced activation of the T-cell-mediated immune system. In vivo, the GM group displayed lower levels of pro-inflammatory factors and less pronounced Th1/Th2 imbalance compared to the unmodified gliadin group. Notably, the GM also improved the balance of the intestinal microbiome. In brief, GM exhibited significantly reduced celiac toxicity in both cellular and animal models that mimics the intestinal environment of celiac disease. These findings suggest that transamidation treatment holds potential as a safer alternative strategy to lower the toxicity of wheat gliadin/wheat flour, potentially paving the way for developing modified gluten-based foods with desirable texture or ingredients as a nutritional enhancer or structure improver, benefiting individuals with specific needs.

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.

Detoxification of Wheat Gluten by Enzymatic Transamidation under Reducing Condition and Its Application in Typical Food Model

SCOPE

Gluten, the primary network builder of wheat dough, is responsible for celiac disease or wheat allergy. Transamidation of gluten under reduction conditions has been shown to reduce the potential toxicity of celiac disease, but its application in food preparation has not been extensively studied. This work investigates the use of transamidation in food preparation to address this gap in knowledge.

METHODS AND RESULTS

This study investigates the effects of transamidation on the toxicity of commercial wheat flour and the apparent structure, digestive level, and rheological characteristics of resultant dough and steamed bread, as a typical food model. The results show that transamidation starts at the kneading stage, as evaluated by using R5 enzyme-linked immunoassay and rat basophils. The potential toxicity of celiac disease is reduced by about 83% when 1% microbial transglutaminase (mTG), 2% l-lysine, and 1% reduced glutathione (GSH) are added, while retaining the original physical and rheological properties of wheat flour. The additional of reduced GSH also improves the in vitro protein digestibility.

CONCLUSIONS

Although it cannot be a celiac disease treatment directly, this study suggests that transamidation can serve as an alternative method for reducing the gluten toxicity of wheat flour-based food products.

Celiac Disease: Disease Models in Understanding Pathogenesis and Search for Therapy

Celiac disease is a complex polygenic systemic disorder caused by dietary gluten exposure that selectively occurs in genetically susceptible people. The potential celiac disease is defined by the presence of celiac disease-specific antibodies and compatible human leukocyte antigen but without histological abnormalities in duodenal biopsies. At present, the only treatment is lifelong adherence to a gluten-free diet. Despite its effectiveness, the diet is difficult to maintain due to its cost, availability of gluten-free foods, and hidden gluten. The need to develop non-dietary treatment methods is widely recognized, but this is prevented by the absence of a pathophysiologically relevant preclinical model. Nonetheless, in vitro and in vivo models have made it possible to investigate the mechanisms of the disease and develop new treatment approaches: The use of foods with neutralized gluten, microbiota correction, cocktails of specific endoproteinase, polymer gluten binders, specific inhibitors of transglutaminases and inflammatory cytokines, and a vaccine based on allergen-specific therapy.

L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications

Tea (Camellia sinensis L.) is a very popular health drink and has attracted increasing attention in recent years due to its various bioactive substances. Among them, L-theanine, a unique free amino acid, is one of the most important substances in tea and endows tea with a special flavor. Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects. Due to the unique characteristics and beneficial functions, L-theanine has potential applications in the development of functional foods. This review summarized the influencing factors of L-theanine content in teas, the main health benefits and related molecular mechanisms of L-theanine, and its applications in food, understanding of which can provide updated information for the further research of L-theanine.

Advances in quantification and analysis of the celiac-related immunogenic potential of gluten

Gluten-free products have emerged in response to the increasing prevalence of gluten-related disorders, namely celiac disease. Therefore, the quantification of gluten in products intended for consumption by individuals who may suffer from these pathologies must be accurate and reproducible, in a way that allows their proper labeling and protects the health of consumers. Immunochemical methods have been the methods of choice for quantifying gluten, and several kits are commercially available. Nevertheless, they still face problems such as the initial extraction of gluten in complex matrices or the use of a standardized reference material to validate the results. Lately, other methodologies relying mostly on mass spectrometry-based techniques have been explored, and that may allow, in addition to quantitative analysis, the characterizationof gluten proteins. On the other hand, although the level of 20 mg/kg of gluten detected by these methods is sufficient for a product to be considered gluten-free, its immunogenic potential for celiac patients has not been clinically validated. In this sense, in vitro and in vivo models, such as the organoid technology applied in gut-on-chip devices and the transgenic humanized mouse models, respectively, are being developed for investigating both the gluten-induced pathogenesis and the treatment of celiac disease. Due to the ubiquitous nature of gluten in the food industry, as well as the increased prevalence of gluten-related disorders, here we intend to summarize the available methods for gluten quantification in food matrices and for the evaluation of its immunogenic potential concerning the development of novel therapies for celiac disease to highlight active research and discuss knowledge gaps and current challenges in this field.

L-Theanine affects intestinal mucosal immunity by regulating short-chain fatty acid metabolism under dietary fiber feeding

To investigate the effects of l-Theanine (LTA) on intestinal mucosal immunity and the regulation of short-chain fatty acid (SCFA) metabolism under dietary fiber feeding, a 28-day feeding experiment was performed in Sprague-Dawley rats. The results show that LTA increased the proportion of Prevotella, Lachnospira, and Ruminococcus while increasing the total SCFA, acetic acid, propionic acid, and butyric acid contents in the feces. LTA also increased IgA, IgE, and IgG levels in the ileum, and increased villi height and crypt depth. Moreover, LTA upregulated the mRNA and protein expression of acetyl-CoA carboxylase 1, sterol element-binding protein 1c, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase in the liver, while downregulating the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon. Our study suggests that LTA can affect intestinal mucosal immunity by regulating SCFA metabolism under dietary fiber feeding.