Effect of extrusion conditions on physicochemical characteristics and anthocyanin content of blue corn third-generation snacks

Abstract

The aim of this study was to evaluate the effect of barrel temperature (BT, 98.8–141.2°C) and feed moisture (FM, 19.93–34.07%) as independent factors on physicochemical characteristics of microwave-expanded extruded third-generation (3G) snacks obtained from blue corn and corn starch. Single-screw laboratory extruder and a central, composite, rotatable experimental design were used. Both independent factors showed significance (p ≤ 0.01) on most of the analyzed responses. The mathematical models showed values of R2Adj ≥ 0.76 and p of F(model) ≤ 0.001. The optimum area of the extrusion process ranged from 120°C to 126°C for BT and from 23.8% to 25.2% for FM. In optimal conditions, the product showed an expansion index of 4.8, a penetration force of 12.42 N, a specific mechanical energy of 169.08 kJ/kg, and 71.09 mg of total anthocyanin content/kg. The developed 3G snack presented high-quality physicochemical characteristics, with the potential health benefits derived from nutraceutical characteristics (dietary fiber and anthocyanins) of the whole blue corn used.