A process for the preparation of food‐grade rice bran wax and the determination of its composition

Abstract

Abstract A two‐step method was developed for the preparation of food‐grade wax. The first step involved the solventdefatting of crude wax, which gave a dark brown, dry, powdered wax with a m.p. of 75–79°C. The major impurity in the defatted wax was the dark brown resinous matter. In the second step, the resinous matter was removed by bleaching with sodium borohydride in isopropanol. This step yielded a pale yellow, odorless wax with purity higher than 99% and with a m.p. of 80–83°C. The resinous matter was a mixture of aliphatic aldehydes, fatty alcohols, and FA. High‐temperature GC analysis of the purified rice bran wax indicated that it contained 11 major and 9 minor types of saturated wax esters. The major and minor peaks contained C 44 –C 64 and C 45 –C 59 wax esters, respectively. Rice bran wax was mainly a mixture of saturated esters of C 22 and C 24 FA and C 24 to C 40 aliphatic alcohols, with C 24 and C 30 being the predominant FA and fatty alcohol, respectively. The alcohol portion of the wax esters also contained small amounts of branched and odd carbon number fatty alcohols.