COLD SOAKING TEMPERATURE REACTION ON MACHINE PERFORMANCE PARAMETERS OF DESI-RED PADDY RICE

An efficient use of machine depends on several factors such as machine parameters, product parameters, environmental and human factors. However, in this work, the effect of Desi-Red Paddy (DRP) rice soaking parameters on machine performance parameter was examined. Desi-red paddy rice sample was used to evaluate a medium-scale rice processing plant developed at University of Ibadan, Nigeria and the sample was bought from local farmers in Akure, Nigeria. The paddy rice was soaked at different soaking temperatures (5, 10 and 20oC) and soaking time ranged (2-4 h). Sensory method was used to recognize rice colour after dehulling. The machine used, was evaluated using standard methods of Dehulling Efficiency (DE), Dehulling Capacity (DC) and Percentage Broken Rice (PBRi). Central composite design (ANOVA at α0.05), was used for analysis. The DE of 87.7, 91.6, 94.4 %; DC of 222.73, 269.54 and 145.84 kg/h; and PBRi of 12.0, 8.02 and 4.0 % were obtained at soaking temperature of 5, 10 and 20oC, and ranged time of 2-4 h respectively. Optimum processing parameters were 57.25℃ soaking temperature and 2.3 h soaking time. The effect of soaking parameters was significant on PBRi but not significant on DE and DC at P < 0.05. It was observed that DRP rice dehulled at soaking temperature of 10oC was whiter than 5 and 20oC. This shows that rice structural cell was destroyed at a very low or high temperature. Percentage broken rice (12, 8.02 and 4.0 %) obtained were far below the international standard of 20 % for milled rice. Optimal soaking conditions considerably reduce rice breakage without affecting dehulling efficiency or capacity. Soaking at the appropriate temperatures improve rice quality, meeting international milling standards.