Effect of replacing rice flour with raw and sprouted mung bean flour on the physico-chemical characteristics of gluten-free batter and cake

Cake is one of the products consumed by the baking industry, which has an important place among people due to its change in taste and appearance, long shelf life (about 4 weeks) and ease of consumption. Normally, this product is produced with wheat flour that contains gluten. Gluten is a combination of food products found in some grains, such as gliadins and glutenins in wheat, hordins in barley, and secolins in rye, which causes an immunological reaction in celiac patients. Today, the only way to treat this disease is to use a gluten-free diet throughout the patient's life. a gluten-free diet prohibits the consumption of bread, cereals or other foods made from wheat, barley, oat, rye and triticale flour. For this purpose, gluten-free cereals (rice, millet, sorghum and corn) and pseudo-cereals (quinoa, buckwheat and amaranth) can be used in the production of gluten-free products. In the process of rice milling to prepare white rice, a significant part of its minerals and fiber is lost, in the preparation of gluten-free products based on rice flour, the flour of other cereals, the flour of some legumes, or permitted additives should be used so that the resulting product is Nutrients have a good balance and meet the needs of celiac patients, also in rice-based products, compared to wheat-based products, the technological quality is lower due to the lack of proteins forming the viscoelastic network of gluten. producing and improving the characteristics of gluten-free products for celiac patients is one of the most important challenges in the food industry. For this reason, the aim of this study was to investigate effect of replacement of rice flour with raw and sprouted mung bean flours in order to improve the physicochemical characteristics of gluten-free cake and dough. Mung beans with the scientific name Vigna radiate is an annual plant belonging to the Fabaceae family and is a cheap and convenient source of protein, minerals and vitamins and belongs to the group of gluten-free legumes. Whole mung bean contains several anti-nutritional factors such as saponin, phytic acid and tannin. Sprouting is a conventional and inexpensive way to improve the nutritional properties of legumes, and during this process, a significant part of these factors removed. During germination, which is a natural process during seed growth, the stored compounds that are usually used for respiration and the synthesis of new cells before the growth of the embryo are destroyed and complex biochemical and physiological reactions occur that cause extensive changes in the composition or morphology of the beans. In the present study, the effect of 4 levels of raw and sprouted mung beans (5, 10, 15 and 20%) on the specific weight and consistency of the cake batter, as well as the volume and porosity, moisture and textural features of the gluten-free cake based on rice flour in a completely randomized design with 9 treatments were investigated. The results of analysis of variance showed that the use of whole and sprouted mung bean flour in the cake formulation led to a significant decrease (P<0.05) in the specific weight of the dough compared to the control sample, which could be due to the trapping of more air bubbles in the cake dough. The highest specific weight was related to the control sample and the lowest specific weight was related to TM15 treatment. The addition of sprouted mung bean flour at different replacement levels caused a significant (P<0.05) increase in dough consistency compared to the control sample containing 100% rice flour, and this increase was more significant when 20% of sprouted mung bean flour was used. Also, the addition of whole mung bean flour to the formulation caused a significant increase in the consistency of cake batter compared to the control sample, but the use of 15% and 20% levels of whole mung bean flour was not significantly different from each other. The reason for increasing the consistency of cake batter can be attributed to the increase in water absorption capacity and water trapping and connection with the protein network of batter flour, which leads to a decrease in their mobility. On the other hand, the presence of more protein in whole and sprouted mung bean flour can be another reason for increasing the dough consistency of cakes containing mung bean flour compared to the control sample. By examining the results of the effect of adding whole and sprouted mung bean flour on the cake volume index, it was found that the samples containing whole and sprouted mung bean flour increased this component at a significant level (P<0.05) compared to the control sample, the reason for which can probably be The high amount of protein in mung beans and the subsequent increase in the creation of protein networks as well as the improvement of protein network formation due to the increase in mung bean flour proteins and the increase in gas retention were attributed. The lowest specific volume related to the control sample and also the cake containing 20% sprouted mung bean flour had the highest specific volume compared to other samples. The improvement of the specific volume in these treatments can be related to the increase in the consistency and viscosity of the cake batter, and these changes increase the entry of air bubbles into the cake batter during mixing, as well as the storage capacity of the air bubbles inside the cake during baking. The results of the effect of adding raw and sprouted mung bean flour in the rice-based gluten-free cake formulation showed that the control sample had the lowest porosity and the TS20 treatment, which contains the highest amount of sprouted mung bean flour, had the highest porosity. The porosity of the treatments when sprouted mung bean flour was used was more than the porosity of the samples that used raw mung bean flour. The reason for this can be attributed to the amount of protein of mung bean flour combined with rice flour, which by increasing it to a certain amount, causes the stability of gas cells and delay in staleness. Also, the increase in porosity can be due to the decrease in size and increase in the number of gas cells and its uniform distribution in the product texture. in the present study, a direct relationship between volume and porosity was observed. on the baking day, the moisture content of the cake core increased significantly (P<0.05) when using sprouted mung bean flour at levels of 5-20% and whole mung bean flour at levels of 15 and 20% compared to the sample prepared from 100% rice flour. The sample prepared from the TS20 treatment had a higher moisture content than the other sprouted and whole mung bean flour treatments. Most of the changes were significant until the third day, and on the seventh day of storage, the moisture content of the samples decreased slightly, and as in the previous two days, the TS20 treatment sample had the highest moisture content. The increase in moisture content of cakes containing mung bean flour can probably be due to the absorption of more water and the ability to maintain more moisture of mung bean flour than rice flour. the cake core hardness of all samples increased with increasing storage time. The decrease in moisture and the easier migration of moisture from the core of the cake to the cake shell as a result of the absence of gluten is the main cause of staleness in gluten-free products. According to the results obtained from the hardness of the cake core texture on the same day of baking, it was found that increasing the amount of mung bean flour (raw and sprouted) reduces the hardness of the cake texture. The highest hardness on the day of cooking was related to the control treatment, which had a significant difference (P<0.05) with other treatments, and the lowest hardness was related to the TS20 treatment. The decrease in hardness in cakes prepared with rice and mung bean flour with increasing mung bean ratio is probably because the contents of fiber, lipids and proteins, by affecting gelatinization and staleness, cause a decrease in hardness. As a result, the results of this study showed that the use of sprouted mung bean flour has the potential to improve the quality characteristics of gluten-free batter and cake samples. In this way, to increase consumer demand for products without artificial additives, the use of sprouted mung bean flour can improve the quality of gluten-free products. According to the results of this study, the use of 20% sprouted mung bean flour can improve the quality of gluten-free products.