Lipid Components of North American Wild Rice (Zizania palustris)

The content and composition of fatty acids, sterols, tocopherols, and gamma-oryzanol in wild rice (Zizania palustris) grown in North America were compared with those in regular brown rice (Oryza sativa L.). The lipid content of wild rice ranged from 0.7 to 1.1%, compared with 2.7% in regular brown rice. The lipids of wild rice comprised mainly linoleic (35-37%) and linolenic (20-31%) acids. Other fatty acids included palmitic (14.1-18.4%), stearic (1.1-1.3%), and oleic (12.8-16.2%). Wild rice lipids contained very large amounts of sterols, ranging from 70 g/kg for a Saskatchewan sample to 145 g/kg for Minnesota Naturally Grown Lake and River Rice. The main sterols found in an unsaponified fraction were: campesterol (14-52%), beta-sitosterol (19-33%), Delta(5)-avenasterol (5-12%), and cycloartenol (5-12%). Some of sterols, gamma-oryzanols, were present as the phenolic acid esters; the amount ranged from 459 to 730 mg/kg in wild rice lipids. The largest amounts of tocopherols and tocotrienols, 3682 and 9378 mg/kg, were observed in North Western Ontario wild rice samples, whereas the lowest were 251 mg/kg in an Athabasca Alberta sample and 224 mg/kg in regular long-grain brown rice. The alpha isomer was the most abundant among tocopherols and tocotrienols. The results of this study showed that wild rice lipids contain large amounts of nutraceuticals with proven positive health effects.