Physicochemical and sensory properties of corn grits and pineapple stem starch-based extruded snacks enriched with oyster mushroom powder

This study aimed to evaluate physicochemical and sensory characteristics of corn grits and pineapple stem starch-based extruded snacks enriched with oyster mushroom powder (OMP). Base materials (corn grits and pineapple stem starch at a ratio of 1:1) were mixed with OMP at levels of 5, 10 and 15% (w/w, total dry ingredients basis). The mixtures of dry ingredients were adjusted to 15% moisture content, followed by adding 4% palm oil. The mixtures were kept at room temperature overnight before being extruded using a twin-screw extruder with barrel temperatures of 80–140 °C and screw speed of 450 rpm. Increasing levels of OMP resulted in increased bulk density, hardness, redness, cell wall thickness, total phenolic content and antioxidant activity of extruded snacks but decreased expansion ratio, lightness and yellowness values. X-ray diffraction showed that extruded snacks with increasing levels of OMP resulted in higher amounts of V-type crystals, indicating to the greater formation of amylose-lipid complex. Sensory evaluation showed that extruded snacks with 5% OMP had the highest preference levels for all sensorial attributes. This study demonstrates that pineapple stem starch and OMP can be used to produce nutritionally enriched and acceptable extruded snacks.