RHEOLOGICAL PROPERTIES OF DOUGH AND QUALITY OF GLUTEN-FREE AMARANTH PASTA AT VARIOUS DEGREES OF STARCH GELATINIZATION

Abstract

Expanding the range of high-quality products for targeted nutrition requires the implementation of advanced technologies for processing pseudocereals. Amaranth flour is a promising raw material due to its high content of complete protein and hydrophilic sites; however, the absence of a gluten network complicates the formation of a stable structure in gluten-free pasta. The aim of the study is to optimize the formulation of gluten-free pasta based on amaranth flour by determining the optimal level of incorporating a pre-gelatinized flour paste and evaluating its effect on the rheological properties of the dough and the physicochemical characteristics of the finished extruded products. Laboratory tests were conducted using an extrusion molding method with a fixed dough moisture content of 40%. The study investigated the effect of incorporating pre-gelatinized flour paste at levels of 15%, 25, and 35% of the total flour mass (paste water-to-flour ratio of 1:4). Dough rheological properties, optimal cooking time, final moisture content, titratable acidity, and water absorption coefficient were evaluated. The results were processed using mathematical statistical methods (P<0,05). It was established that, without heat treatment of the raw material, the dough is highly brittle due to the lack of gluten. The gelatinized amylopectin starch in the scalded mixture acts as a structural matrix, forming a three-dimensional network that holds the starch granules in place. Incorporating 15% and 25% of the scalded mixture extends the cooking time to 3.7±0.1 min and 4.2±0.2 min, respectively, compared to the control (3.2±0.1 min). It was determined that the incorporation of 25% scalded flour mixture ensures the maximum water absorption capacity (162±6%) and minimal loss of dry matter into the water (6.2±0.3%), a figure 2.2 times lower than that of the control. Conversely, the addition of an excessive amount of the scalded phase (35%) – due to a lack of free water – leads to the breakdown of the protein-starch matrix under the influence of shear forces within the extruder; this increases dry matter loss to 8.4% and raises the final moisture content to 12.18±0.15%. The titratable acidity of the samples ranged from 3.4 to 4.1 degrees, ensuring storage stability. The optimal proportion of gelatinized flour was determined to be 25%; this ensures the formation of a continuous hydrocolloid gel that encapsulates flour particles and guarantees high-quality characteristics for the finished gluten-free product in accordance with Clean Label principles.