Comparative study of methyl-tert-butyl ether extractives from rye and ricestraw

The chemical composition of lipophilic extractives from rye and rice straws has been comparatively examined. Free fatty acids (19.04-22.95%), sterols (12.54-14.60%), waxes (9.53-27.14%), steryl esters (16.02-18.19%), and trig lycerides (5.72-11.38%) were identified as the five major classes of lipids in the two straw extractives. Minor components of diglycerides (0.23-0.42% ) and resin acids (0.05-0.12%) were also verified from the two straw lipoph ilic extracts. Of the individual compounds in each group, fifteen free fatt y acids, four sterols, three waxes, five steryl esters, and three triglycer ides were quantitatively determined. The most abundant saturated free fatty acids were palmitic acid (C16:0, 3.96-4.24%) and tetradecanoic acid (C14:0 , 2.95-3.62%), whereas linoleic (C18:2) and/or oleic (C18: 1) acids (1.87-2 .09%) were the most dominant unsaturated free fatty acids, p-Sitosterol was identified as a predominant component, accounting for 83.89% of the total sterols in rye straw extract and 94.45% in rice straw extractives. Palmitic acid palmityl ester was verified as a dominant component in a group of wax es, accounting for approximately 70% of the waxes analyzed in the two extra cts. The steryl esters analyzed were composed mainly of steryl laurate (0,2 9-0.95%), steryl myristate (3.20-3.56%), steryl palmitate (1.86-2.28%), ste ryl margarate (2.20-2.93%), and steryl oleate (2.13%). Of the triglycerides verified, glyceryl tripalmitate (0.23-1.64%), 1,2-dipalmitoyl-3-oleoyl-rac -glycerol (1.06-2.08%), and triolein (cis-9) (0.77-1.61%) were identified i n this group.