Extraction and characterization of lipophilic extractives from wheat straw. II. Spectroscopic and thermal characterizations

Successive extraction of wheat straw with hexane at 70degrees, hexane-chloroform (5/1, v/v) at 600, chloroform at 55degrees, diethyl ether-acetic acid (9812, v/v) at 30degrees, and methyl tert-butyl ether at 50degrees for 2 h yielded 0.52, 0.47, 0.29, 0.08, and 0.10% extractives, based on dry straw. Free fatty acids (16.0-43.8%), sterols (3.8-22.4%), waxes (3.0-23.4%), steryl esters (9.5-15.0%), and triglycerides (4.5-13.6%) were identified as the major five classes of lipids in the wheat straw extractives. In this study,the five successive fractions of the lipophilic extractives were investigated by spectroscopic techniques such as Fourier transform infrared and carbon-13 nuclear magnetic resonance and thermal analysis.