ABSTRACT

This study was carried out in order to evaluate the effect of extrusion conditions on the physico-chemical properties of corn grits-raspberry seeds snacks. The raspberry seeds were chosen to fortify the corn-based snack due to their richness in ellagic acid, a natural phenol antioxidant which has a beneficial effect on human health. Extrudates were prepared using a laboratory single-screw extruder, operated at different conditions. Box-Behnken experimental design was used to evaluate the impact of processing variables: moisture content (18-25%), temperature of extrusion (100-200 °C) and content of raspberry seeds (0-20%) on expansion index, hardness and ellagic acid content. Snack with the highest expansion (2.15) was obtained under 18% moisture, 150 °C temperature and 0% of raspberry seeds content. The highest content of ellagic acid (609.54 mg/kg) was reported in the samples with 20% of raspberry seeds, 100 °C temperature and 21.5% moisture. Extrudates obtained under conditions of 0% raspberry seeds, 100 °C temperature and 21.5% moisture showed the highest hardness value (53.34 kg). It was concluded that changing one or more parameters in the extrusion process can significantly affect the characteristics of the obtained product, and that raspberry seeds have a great potential in food fortification.