Phytochemical content and antioxidant activity of extruded products made from yellow corn supplemented with apple pomace powder

The aimed of this study was quantified total phenols content, total flavonoids, and antioxidant activity in extruded ready-to-eat products made from yellow corn added with apple pomace powder. A central composite rotatable experimental design was used. The variables tested were exit die temperature (140-180 degrees C), feed moisture (14-20 g/100 g) and apple pomace concentration (0-30 g/100 g). The effect of the process variables on the total contents of phenols, flavonols, flavanols and flavonoids and antioxidant activity was evaluated using the response surface methodology. The data of each response were fitted to a second-order model with determination coefficients >= 0.71. The extruded product with no added apple bagasse showed the lowest values of the evaluated phytochemicals but had higher antioxidant activity by DPPH. The addition of apple pomace increased the phytochemical content and antioxidant activity in extruded ready-to-eat products made with yellow corn. This makes it possible to obtain a formulation of an extruded food rich in phenolic compounds with potential to contribute to prevention of oxidative stress, while making use of agro-industrial waste from apple juice extraction.