Development of multigrain extruded flakes and their sensory analysis using fuzzy logic

Abstract

Present research involves the development of nutritious multigrain flakes from rice flour, black gram flour and flaxseed flour mixture and using extrusion, flaking followed by microwave roasting. The effect of feed moisture content, [25–35% (wb)] and extrusion process variables barrel temperature (60–80 °C) and screw speed (250–300 rpm) on physicochemical and bioactive properties of extruded beads was studied. The results indicated that feed with higher moisture content produced beads with lesser diameter, however higher barrel temperature contributed to increased bead diameter up to 7 mm. Extrusion process caused TPC and AA to decline by 26% and 47% respectively due to thermal degradation. Further, extruded beads were flaked and influence of microwave roasting power (540–900 W) and treatment time (1–4 min) on functional attributes of flakes was evaluated. During the roasting, moisture of the flakes was reduced from the 18% to below 4% for long term safe storage. Higher power caused faster removal of moisture, consequently, reducing the roasting time. Roasting of flakes at 900 W for more than 2 min caused surface burning, which increased the browning index. Analysis of FTIR spectrum of raw and flakes powder revealed a reduction in peak intensity along with the shift in peak position, which could be due to functional group changes caused by extrusion and microwave roasting. Additionally, the roasted flakes were tested for sensory acceptability using fuzzy logic of sensory data and revealed that flakes produced from roasting at 900 W for 2 min had higher superior acceptability.