Evaluation of Polishing Properties of Rice Varieties for Sake Brewing on the Laboratory-scale Polishing Machine

Studies on Quality Evaluation of Rice for Sake wrewing (Part 4)

Abstract

A simplified method using a laboratory-scale, small capacity polishing machine, for evaluation of polishing properties of rice varieties for sake brewing was studied. Of 12 methods studied, 3 methods: ratio of cracked rice grain, ratio of rice grain with residual embryo, and ratio of rice grain with residual groove, were found to be essential for the evaluation of polishing properties. By using these 3 methods the polishing properties of 20 rice varieties cultivated in the same conditions at Sake Brewer's Rice Experimental Farm, Hyogo Agricultural Research Center in 1992 and in 1993, were compared. As the results, the polishing properties of Nipponbare and Shirayukihime varieties were evaluated to be superior to those of the rest of the varieties tested for the two years. The relative evaluations of 1992 rice samples were almost equivalent to those of 1993 rice samples. The results suggest that the polishing properties are characteristic to each rice variety itself. Relative evaluation of the polishing properties of 2 rice varieties on the laboratory-scale polishing machine was found to be the same for that on the factory-scale polishing machine.