Physicochemical, sensory and nutritional evaluation of gluten-free bread based on rice and soybean flourIntroduction

Abstract. The growing demand for gluten-free products has favored the development of numerous bakery products seeking to reach similar quality characteristics than original wheat products. The objective of this study was to obtain a formulation of a baked product without gluten using rice and soybean flour, integrating technological, sensorial and nutritional aspects. The study included the evaluation of two formulas of rice-soybean flour (50-50 and 70-30) and one control (wheat flour). For each formulation, the chemical analysis (official AOAC techniques), physicochemical properties (color, texture, aw) and an evaluation of sensorial attributes using a hedonic scale with a panel of 30 non-trained judges were performed. The protein digestibility-corrected amino acid score (PDCAAS) according to FAO's amino acid pattern and glycemic index were evaluated. An analysis of variance and multiple comparison of means of the results were applied. According to the statistical analysis, formulation with 70% of rice flour and 30% of soybean flour obtained similar sensorial acceptance as the formula 50-50, higher protein content (24.6%) with a protein quality of 92.2% and the lowest glycemic index (27.63). The control wheat formulation had a protein content of 8.6%, with a protein quality of 49.4%. However, the 70:30 gluten-free formulation showed higher firmness (143.4 N) with respect to the control (29.4 N) and different color (lower L* and b* parameters). The caloric content of a portion of gluten-free formulas contributes approximately with 19% of the calories according to the DRI for a diet based on 2000 kcal. These formulations are a good choice not only for celiac patients, but for anyone who wants to consume breads with high protein content and good digestibility.