Effects of roasting conditions on the properties of Amaranth (Amaranthus cruentus L.) grain using response surface methodology

Abstract

Industrial applications of amaranth seeds (Amaranthus species L.) have not been fully explored, which may be due to dearth of information on its various forms of use or applications. Roasting is one of such ways amaranth grain can be processed for immediate snacking or preparation prior to use for varying other purposes. The focus of this study was on the effect of roasting conditions on the properties of amaranth grain, using response surface methodology design to develop, improve, and optimize the process. Data was analyzed using regression and analysis of variance (ANOVA) at α 0.05. Five levels of roasting temperature and durations were employed. The roasted amaranth seeds were subjected to evaluation for proximate, colour, functional and sensory properties using standard methods. Effect of roasting conditions on properties were modeled and optimized. The roasting conditions had a significant effect on the proximate, colour, functional and sensory properties of roasted amaranth seeds. The optimal roasting conditions were a roasting temperature of 180 °C, roasting duration of 8 mins with desirability of 0.69. The optimum roasting conditions resulted in roasted amaranth seeds with protein of 16.26%, moisture of 18.30%, ash of 1.86%, fat of 2.22%, crude fibre of 8.92%, carbohydrates of 52.70%, bulk density of 1.29%, Oil Absorption capacity of 6.26 g/g, water absorption capacity of 9.20 g/g, solubility of 6.49%, swelling power of 14.16%, colour of 198.31°, and overall sensory acceptability score of 7.20. Roasted amaranth grains or its flour creates a value added product from amaranth grain which could be used as is for varying purposes, or in composite form for diverse uses.