Modelling and optimization of the extrusion process in a snack of barley/corn and nutritional evaluation of the optimized product

Background and objectives: Most of the snacks in the market contain a single cereal and show nutritional deficiencies. The aim of the study was to optimize the conditions of the extrusion process for a snack with barley/corn mix and their physicochemical evaluation, amino acid content, protein digestibility, and resistant starch as a healthy snack. Findings: The regression model indicated that the variables water absorption index, water solubility index, and hardness can be explained by the models. Expansion index showed no significant effect. The optimal conditions of the process of extrusion were feed moisture 38%, die temperature 130°C, and barley/corn mix 50:50. An unflavored snack with 392.11 kcal/100 g was obtained, considering it is flavored, its estimated energy contribution is around of 446.11 kcal/100 g. The concentration of essential amino acids in the extrudate meets the requirements established by FAO/WHO/UNU for children and adolescents. Protein digestibility increased and the content of available and resistant starch was reduced. Conclusions: The optimal conditions of extrusion allowed to obtain an alternative snack with the essential amino acid requirements and higher protein digestibility. Significance and novelty: The combination of two cereals allows to supplement the requirement of essential amino acids and greater protein digestibility.