摘要：Extrusion cooking is an ideal method for the manufacture ready-to-eat snacks. The benefits include increased protein and starch digestibility in protein-enriched cereal snack products. Extrusion cooking needs to be controlled if product quality is to be maintained. Extrusion cooking was carried out at barrel temperature of 110°C - 150°C, screw speed of 350 - 450 rpm, and feed moisture of 12% - 14% to investigate the effect of extrusion conditions on physical properties (expansion ratio and bulk density) of a rice, sorghum and soy flour blend. From response surface analysis, expansion ratio and bulk density were found to be significantly (P 0.05) effect. Expansion ratio and bulk density ranged from 2.0 to 2.6 and 0.79 to 0.95 g/ml respectively. One hundred grams of the extruded product would supply 45% of the recommended daily allowance for protein in children aged up to 12 years. The mineral content in 100 g extrudates was found to be 52 mg calcium, 3.01 mg iron and 1.23 mg zinc. The retention of amino acids in the extruded products was 88% - 95% with lysine—a limiting amino acid in cereals having a loss of 9.1% after extrusion. Extrusion conditions can be optimized to produce ready-to-eat snack products with high expansion ratio, low bulk density and a good nutritional profile to meet the growing consumer needs for nutritious ready-to-eat snack products.
