Investigating damage properties of rice grain under compression load

Abstract

In order to optimize the design of milling machinery for rice varieties, it is important to understand the mechanical properties such as strength and damage properties of grains of different varieties of rice. The ratio of amylose of rice not only affects the texture of cooked rice but also the mechanical properties of raw rice grain. In this study, the damage properties of different breeds of rice with three different levels of amylose ratios were investigated. The damage properties were investigated by using compression and three point bending tests. The compression tests were conducted on rice specimens with two parallel surfaces made from rice grains and the three point bending tests were conducted on whole rice grains. Although the compression force to break rice kernel under 3 point bending are similar for all types of rice under tests. It can be seen that, among the rice varieties under tests, Chainat 1, the high amylose ratio rice, has the highest compression strength. The understanding of this study can help the developing of methods and devices used for milling processing of rice with different level of amylose to reduce the milling losses.