PREDICTION AND VALIDATION OF PHYSICAL QUALITIES OF OFADA RICE AS AFFECTED BY STORAGE DURATION AND PROCESSING CONDITIONS USING RESPONSE SURFACE METHODOLOGY

摘要

The objective of the study was to produce optimum physical qualities of Ofada rice with varying independent variables of storage duration and processing conditions using response surface D-Optimal. The experimental design independent variables were storage duration (1 - 9 months) and processing conditions (soaking, 1-5 days; parboiling, 80-120C; drying, 30 -70C) and responses were size characteristics, head rice yield, brokenness, chalkiness and colour value. The experimental results were evaluated, optimised and modelled using response surface methodology. The result revealed that storage duration and processing parameters affected physical quality of Ofada rice. The predicted R2 ranged between 0.9148 and 0.7373 which confirmed the fitness of the model. Coefficient of the quadratic model showed the effect of soaking time influence positively size characteristics, brokenness, chalkiness and colour value. Parboiling and drying temperature determined head rice yield, parboiling positively influence colour value of Ofada rice while the effect of paddy storage was more felt on lightness. The best optimum solution for storage and processing conditions as predicted include storage of paddy for 1 month, soaking in water for 1 day, parboiling at 119.92°C and drying at 30.32°C.