Desenvolvimento de pão de forma sem glúten com farinha de arroz vermelho, enzima transglutaminase microbiana e prebiótico: avaliação tecnológica, sensorial e armazenabilidade.

Abstract

This research aimed to characterize the red rice flour and formulate gluten-free bread for celiacs, applying microbial transglutaminase enzyme as the adjunct of baking and prebiotic (inulin) and verify the effect on the technological, sensorial quality and storability of the breads. First, it determined the physical-chemical, granulometric, morphological characterization and the minerals present in the red rice flour were determined. Red rice flour (FA), sweet manioc starch (PD) and its mixtures (100% FA, 75% FA and 25% PD, 50% FA and 50% PD, 100% PD) were submitted to rheology analysis (RVA), Fourier transform infrared (FTIR) absorption spectroscopy, X-ray diffraction and differential exporatory calorimetry (DSC). In the second stage, processing of gluten-free breads and physical, physical-chemical, sensory and storageability were performed. The breadmaking process was studied by a full factorial design 23 with 3 experiments in the central point, and the independent variables [(% microbial transglutaminase enzyme and fermentation time (min)].The dependent variables in the experimental planning were: Color (L *, a * and b *), water content, acidity, pH, specific volume, firmness, elasticity, chewiness and cohesiveness. We were used to evaluate the sensory characteristics of bread an acceptance test and purchase intent with 60 judges untrained. The storage formulations of gluten-free form loaves under freezing at -18 ° C were studied over a period of 90 days and were periodically evaluated at baseline and at predetermined intervals of 01, 05, 15, 30, 60 and 90 Days in relation to color (L *, a * and b *), pH, acidity, firmness and specific volume. The red rice flour showed granulometry indicated for the production of bakery products, and it is not possible to describe an exact geometry for the particles. Showed high concentration of fibers (8,80.g.100g-1), proteins (8,00.g.100g-1), potassium (465,24.mg.100g-1), phosphorus (245,50.mg .100g-1) and zinc (24.44mg 100g-1). The red rice flour and its mixtures with sweet manioc starch presented rheological characteristics suitable for the production of gluten-free breads. The red rice flour presented x-ray diffractograms related to the crystallinity pattern A and the mix with sweet pozzolan type B crystallinity. Regarding statistical planning, it was not possible to establish significant models for water and color attributes (L *, a * and b *). The addition of MTgase and the elevation of its level increased the water content, the specific volume and firmness of the bread chewiness. To cover as many optimized attributes as possible, it was possible to maintain levels of microbial transglutaminase enzyme content between 0.5 and 1.0% with the fermentation time between 60-80 (min). All formulations were well accepted sensorially, with averages above 6.0, except for the softness attribute. The PC formulation (1.0% MTgase and 80 min TF) presented the best attributes, greater acceptance and preference, presenting the highest scores: 5 (would certainly buy) and score 4 (possibl y buy) for the intention analysis of purchase. Gluten-free breads with red rice flour, microbial transglutaminase enzyme and prebiotic (inulin) had acceptable quality characteristics during storage under freezing at -18 ° C for 60 days. These results show that the use of red rice flour and microbial transglutaminase enzyme in gluten-free bread formulations is an option for the celiac public to obtain products with physical and sensory quality.