Physical characterization of maize grits expanded snacks and changes in carotenoid profile
feed moisture, barrel temperature, physicochemical property, carotenoids, extrusion cooking.
The objective of this work was to evaluate the effects of feed moisture (13-17%, wet basis) and barrel temperature (120-160 °C) on physicochemical properties, and changes in the carotenoid profile of maize grits extruded snacks. The extrudates were obtained in a single-screw extruder, according to a factorial design with two replicates. The main effects of feed moisture and barrel temperature on physicochemical properties dominated the process variability. On the other hand, interaction effects dominated on changes in the carotenoid profile, by increasing β-cryptoxanthin and β-carotene, or decreasing lutein and zeaxanthin. The mathematical models developed from responses revealed two feasible operating regions under the domain explored. For a satisfactory process, from a technological and nutritional point of view, it is suggested to extrude at the operating conditions ranging between 13.2-13.7% feed moisture and 120-132 °C barrel temperature. Under these conditions, the specific mechanical energy input required was 410-450 kJ/kg, and extrudates with a volumetric expansion index greater than 12, a crispness work less than 0.4 N.mm, and with moderate increments in the levels of β-carotene and β-cryptoxanthin were produced. The use of richer cultivars in carotenoids could contribute to the production of healthier snacks.