Effect of humidified polisher on the physical quality of milled rice during storage

S. Wahid, R. Ibni Hajar and M.A. Hashifah

Abstract

A study was conducted to evaluate the effect of humidified polisher (as treatment) and friction polisher (as control) on milled rice quality. Dried paddy, Q34 variety was milled using a middle scale commercial mill of 2 t, paddy per hour capacity, located at MARDI Station, Bukit Raya, Kedah. The brown rice produced was further processed by horizontal abrasive whitener and followed by humidified polisher (as treatment) or friction polisher to produce milled rice. Using the cylindrical grader, the head rice was separated from the milled rice. A total of 48 kg of head rice (2 kg per bag for each treatment and control) was packed in polyethylene bags, and stored for 6 months. Samples were taken at monthly intervals for analysis of moisture content, bulk density, head rice, damaged grain, cracked grain, whiteness and insect infestation. In general, all stored samples showed gradual increase in moisture content, but milled rice polished by the humidified polisher had the lowest with significant difference at p = 0.01. The head rice content in treated milled rice (94.41 ± 0.55%) was significantly higher than the control (92.88 ± 0.77%) at p = 0.01. Insect infestation was serious in all samples after 4 months of storage. Cracked grain in treated milled rice was significantly lower than the control at p = 0.01. The whiteness degree of treated milled rice was slightly higher than the control, but not significantly different. No significant difference was found for bulk density and damage between treated and control samples.

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