Nutritional bioactive components of wheat straw as affected by genotype and environment

Policosanol (PC) and phytosterol (PS) enriched dietary supplements and functional foods are marketed for their low density lipoprotein lowering properties. The presence of PC and PS in wheat straw has been reported previously. Wheat straw can be a potential source for recovery of high value components. A fundamental understanding of variations in chemical composition of feedstock is the key for designing efficient processes for value-added product development. Information on variations in the PC and PS content and composition in wheat straw is limited. The objective of this study is to examine the effect of genotype and environment on PC and PS contents and compositions in wheat straw. Samples were collected from three varieties, Jagger, Trego, and Intrada grown at two locations Balko, and Goodwell, OK in 2006. Total PC and PS contents and compositions in the samples were determined by using a gas chromatography system. This study showed that wheat straw contains significant amount of PC (approximately 137-274 mg/kg) and PS (approximately 834-1206 mg/kg). Octacosanol, tetracosanol, docosanol, hexacosanol, and tricontanol were the main PC components. Approximately 60-76% of the total PS consisted of beta-sitosterol. Genotype and environment had a significant effect on PC and PS contents in wheat straw. This is the first study examining the effect of environment and genotype on wheat straw chemical composition. A fundamental understanding of variations of PC and PS contents and compositions in wheat straw requires further research involving samples collected over several years.