Policosanol and other bioactive compounds in different Thai rice varieties

Abstract

This study examines the total lipid, policosanol (PC), tocols, and γ-oryzanol contents, and fatty acid composition in rice bran (RB) obtained from 4 min-polished brown rice of 13 Thai rice varieties, with a new emphasis on the PC content and composition. The total PC content in the oil extracted from RB ranged from 2776 to 7274 μg/g. Sungyod rice had the highest total PC content at 7274 μg/g, followed closely by Niaw Dum Mor at 6407 μg/g, and RD10 at 6308 μg/g. The bran of Thai rice varieties contained triacontanol, dotriacontanol, and tetratriacontanol as their main components. Sungyod rice had significantly more octacosanol. Considering the PC composition, black-pigmented glutinous rice varieties, Leum Pua and Niaw Dum Mor, had higher hexatriacontanol and octatriacontanol levels. The total lipids in rice bran (RB) ranged from 14.9 to 22.1 g/100 g. The key fatty acids found in the Thai rice varieties included oleic acid (37.8–43.0%), linoleic acid (30.3–36.4%), and palmitic acid (14.2–21.6%). In terms of other bioactive compounds, Leum Pua had the highest tocols level at 635 μg/g RB, while Pathum Thani 1 showed an impressive γ-oryzanol level of 4011 μg/g RB. These findings suggest that certain Thai rice varieties have the potential to be rich sources of lipids, PC, and bioactive compounds.