Development of Corngrit-Broken Rice Based Snack Food by Extrusion Cooking

Abstract

Six formulas of corn-based snack were formulated with various ratios of corngrit : calcium carbonate (CaCO₃) : soybean oil. Extrusion processes were conducted by feeding each formula into an extruder at 444 g/min feed rate, employing 300 rpm. Moisture content of the raw materials were adjusted to 16.0±0.5%, with melt temperature of 156–158°C. The product samples exhibiting best physical properties composed of 93 % corn grit, 1 % CaCO₃ 2 % soybean oil, 3 % sugar and 1 % vitamins and minerals mixtures, which was coded as C₆ and exhibited an expansion ratio (E.R.) of 3.90, bulk density (B.D) 70 g/L and compression force (C.F) 69.2 N. However, C₆ corngrit based snack samples possessed the characteristics of overexpanded, crisp friable mouthfeel, orange – yellowish in color and lack of corn odor. Therefore, further developing of C₆, subsequently renamed as CR′0 was undertaken by substituting 10 – 80 % of corn grit with broken rice, resulted in 17 formulas. The corngrit-broken rice snacks were examined for physical properties and then coated with chicken flavor prior to subject to sensory evaluation. Extruded samples produced from 50% of broken rice substitution (CR′₅) was detected to decrease E.R value (3.70) and increase B.D (76.60 g/L) and C.F (96.5 N.) compared to those samples of CR′₀. Among 17 formulas, CR′5 gained the highest scores in flavor and texture preference with the overall acceptability of 7.05, 7.05 and 7.15 (9–point hedonic scale) respectively, which were significantly different at P ≤ 0.05. However, color was not significantly different at P ≤ 0.05 as compared to CR′₀.