Multigrain beverage premix development using extrusion: computational modelling and optimization of process and microstructural characterization
摘要
Pre-processed flours (malted yellow split pea, malted pearl millet, roasted pearled barley, and roasted quinoa blended in 30:30:28:12 w/w ratio) were extruded in twin screw extruder to produce multigrain beverage premix. Its characteristics were modelled using ANN and RSM as functions of die head temperature (X1), speed of screw (X2), and moisture content of feed (X3) varied in ranges: 140–180 °C, 40–50 rpm, and 15–25%, using rotatable central composite design, respectively. Optimum extrusion process conditions achieved using steepest gradient (SA) and genetic algorithms (GA) were in good agreement with following experiment: X1 = 180 °C, X2 = 50 rpm, X3 = 15%, resulting in multigrain beverage premix having high water absorption index (Y1 = 3.46 g g−1), water solubility index (Y2 = 15.10%), and bulk density (Y3 = 0.28 g cm−3), and low total colour change (Y4 = 14.21), specific mechanical energy (Y5 = 28.21 kJ kg−1), and hardness (Y6 = 102.54 N). SEM was used to analyse microstructural properties (Feret’s diameter and circularity) of raw, pre-processed, and extruded multigrain premixes.