Aldehydes in grain sorghum wax

Abstract  Improved knowledge of the properties, composition, and analysis of grain sorghum wax would assist in efforts for industrial application of this product. Wax extracted from grain sorghum, harvested in 1996 in Nebraska, using hot hexane was fractionated with silica gel column chromatography using a series of mixtures of hexane, chloroform, methanol, and acttic acid. During TLC analysis of the sorghum wax, a dark band, which did not appear in carnauba wax, was found between was esters and TAG. This dark band fraction was the primary component, representing more than 40% of the total sorghum wax weight. The purpose of this study was to chemically characterize the dark band. The fraction containing the dark band was subjected to borohydride reduction and autoxidation by exposure to air. The borohydride reduction gave a dark band at the fatty alcohol position on TLC, whereas the oxidized sample showed a dark band at the FA position, strongly suggesting the original dark band contained aldehydes. NMR and GC-MS data confirmed that this fraction contained a saturated C28 aldehyde.