THE INFLUENCE OF GLUTEN-FREE FLOURS ON THE QUALITY INDICATORS OF BISCUIT SEMI-FINISHED PRODUCTS

The article is devoted to the research of applicability of gluten-free flours from cereal crops and from by-products of cereal crop processing - ground crumbs sifted out in a process of flake production from rice, corn and millet during the production of biscuit semi-finished products. Taking into account that viscosity is an important technological characteristic of foam-like biscuit dough, as it determines foam strength and dispersed medium stability, the influence of gluten-free flours on the structural and rheological properties of biscuit dough was studied. It is determined that the substitution of wheat flour for cereal flours leads to viscosity reduction of the dough as a consequence of absence of gluten-forming proteins in them. A comparative analysis of changes in viscous properties of biscuit dough based on flour from flakes crumb while warming it up to 60°C with dough based on cereal flours and dough based on wheat flour was held. It is shown that the presence of partially gelatinized starch granules in flour from flake crumb, as a result of technological peculiarities of their extraction, promotes greater demonstration of thickening properties already at the initial stage of baking than in cereal flours. This leads to an increase of dough viscosity and formation of desired rheological characteristics, which provide the porous structure of finished products. To provide the high quality of gluten-free biscuit semi-finished products, the recipe composition of gluten-free biscuit semi-finished product, based on flour mixture from millet flakes crumb, corn and rice flour, was optimized by using the method of mathematical design of experiments. The porosity indicator was chosen as the criteria for the evaluation of influence of proportion of gluten-free flours on the quality of biscuit semi-finished products. The response surfaces of dependency of biscuit porosity from mass ratio of recipe components in the composite mixture were obtained. It was confirmed experimentally that the use of pre-gelatinized acetylated modified starches during the production of gluten-free biscuit semi-finished products, facilitates the stabilization of the structural and rheological properties of foam structure - viscosity growth of biscuit dough because of foam-stabilizing property, which is particular to them. It was demonstrated that the obtained gluten-free biscuit semi-finished products based on flour composite mixtures with addition of modified starches, had high quality indicators. Based on the results of the research conducted, the recipe was formulated, technological parameters of production of new types of gluten-free biscuit semi-finished products were determined.