Sodium hydroxide (NaOH) concentration and steeping time duration effects on starch production from dry-milled low quality rice IR 64 grade 3 flour using alkaline-protease enzyme digestion method

The low quality rice, such as IR64 grade 3, is processed to produce the rice starch. The production process of the rice starch from low quality rice, IR64 grade 3, is investigated. The process is based on the alkaline protease digestion and alkaline steeping method. The main objective is to obtain high starch content and very low protein content. The enzyme in the process is produced by the fermentation activity of the Bacillus megaterium. The independent variables of this process are steeping time duration and Natrium Hydroxide (NaOH) concentration. Based on the protein content level and the amount of the produced waste, the combination between alkaline steeping and protease-digestion methods produces better quality product compared to the alkaline steeping method. High purity rice starch was produced at conditions 0.05 M NaOH solution and 7 hours steeping duration. The proximate composition of the produced starch has 87.92 % starch, 1.37 % protein, 0.42 % fat and 9.81 % moisture.