Effect of replacement of rice flour with raw and sprouted mung bean Flour on phenolic compounds and physicochemical properties of gluten-Free Bread

Celiac disease (CD), also known as gluten enteropathy or celiac sprue, is one of the most common food-induced diseases in humans. This immune-mediated enteropathy is triggered by the ingestion of wheat gluten and similar proteins in genetically susceptible individuals, where inflammation of the small intestine and hence destruction of the villous structure thereof occur. Celiac disease is a permanent intolerance to certain cereal prolamines with a specific oligopeptidic sequence. The only effective treatment for celiac disease is serious compliance with a gluten-free diet throughout the patient's life. For this reason, the demand for gluten-free products has increased as the number of patients with celiac disease has increased. Production of gluten-free foods, especially baked goods, is usually based on various types of starch, and flour from plants free of gluten, such as maize, rice, soybean and buckwheat. Polysaccharide hydrocolloids and proteins of various origin are typical ingredients that have to be used in exchange to gluten in order to provide appropriate structure of the dough and texture of the final product. Due to the cheap and suitable sources of dietary fiber, carbohydrate, protein, and minerals and vitamins, the beans are a good option for use in gluten-free compounds. Mung bean is one years old plant and belongs to the Fabaceae family. The purpose of this study was to investigate the effect of replacing rice flour with raw and sprouted mung bean flour on the amount of phenolic compounds and physicochemical properties of rice-based gluten-free bread.

For the production of raw mung bean flour, the seeds were washed, dried and milled. To produce sprouted mung bean flour, seed was soaking for 12, 48 and 16 hours, then sprouted and dried, and finally floured. To prepare bread, all dry compounds, other than sugar after weighing, were first screened using a screen of 80 mesh. In this study, four levels of raw and sprouted mung bean flour (5, 10, 15 and 20%) were used. On the produced breads in this study, the effect of 4 levels of raw and sprouted mung bean (5, 10, 15 and 20%) was investigated on the percentage of baking loss, porosity, fat content, L * index, specific volume, phenolic compounds, hardness and total acceptance of gluten free bread in a completely randomized design with 9 treatments.

Based on the results of this study, it was found that the increase in the amount of mung flour and sprouted mung flour until 15% concentration in dough resulted in a non-significant decrease in the amount of baking loss, but the higher amount of baking loss was obtained with increasing of these flour in bread formulation. On the other hand, the results showed that the use of raw and sprouted mung flour compared to the control sample resulted in an increase in the porosity of the samples and the lowest L * index was obtained when the bread formulation containing of 20% raw mung flour. The fat and hardness of the samples increased with increasing of mung flour (raw and Sprouted) and the maximum acceptance rate from the evaluators' viewpoint belonged to the sample containing 10% raw mung flour. Increasing the amount of mung flour in samples increased their phenolic compounds, and in general, increased sprouted mung flour in the formulation compared to raw mung flour resulted in increased phenolic compounds in the samples. Increasing the amount of phenolic compounds during germination is attributed to the need for high oxygen concentrations, which results in more phenolic compounds to protect the cells from oxidative stress. The maximum acceptance rate from the viewpoints of the evaluators was 10% of raw mung flour, which was not statistically significant with control samples and containing 5% of raw and sprouted mung flour. The lowest total acceptance was for the sample containing 20% raw mung flour.

The most important method for preventing celiac disease is using a gluten-free diet. For this purpose, rice flour was used to prepare bread. The results showed that increasing the amount of raw and sprouted mung bean to a concentration of 15% in the formulation resulted in a decrease in the amount of baking loss. On the other hand, increasing the amount of raw and sprouted mung flour in the formulation of breads increased porosity, fat, phenolic compounds and hardness of samples. The lowest L * values of the samples were obtained when 20% of the raw mung flour was used in the formulations of the breads. The maximum total acceptance of evaluators was 10% of the raw mung flour. In finally, it can be stated that the use of raw and sprouted mung flour in amount of 10% and 5%, respectively can be used in bread production.