Influence of bran layer on rice milling quality

Abstract Background and Objectives Rice milling involves applying forces to remove bran from brown rice to produce milled rice. The physical and chemical properties of a rice kernel may affect both the amount of bran removed during milling and the amount of head rice yield (HRY) produced, which is a determinant of crop value. This study investigated bran thickness and bran chemical composition as factors that influence bran removal and HRY as a result of milling. Findings The results showed that brown rice kernels with initial higher surface lipid contents (SLCs) required longer milling times to achieve 0.4% SLC, but the longer milling times did not translate into lower HRYs or higher bran yields. Bran chemical composition had a more significant impact on the milling characteristics than bran thickness. Arabinoxylans had the greatest impact on HRY, followed by lipids and proteins. Conclusions Bran thickness did not have a significant impact on the milling time, bran yield, or HRY. There was significant interaction between arabinoxylans and proteins on HRY and bran yield, which indicates the probability of crosslinking between proteins and arabinoxylans. Significance and Novelty This study demonstrates the importance of rice bran chemical components and their interactions in terms of rice milling quality, rather than their physical properties.