African Journal of Biotechnology Vol. 2 (2), pp. 33-39, February 2003

ISSN 1684-5315  © 2003 Academic Journals  

Variations in fatty acid proportions during desiccation of Telfairia occidentalis seeds harvested at physiological and agronomic maturity

Nkang A*, Omokaro D, Egbe A and Amanke, G 

Department of Botany, University of Calabar, Calabar, Nigeria.

*Corresponding author; E-mail: rankangani@yahoo.com

The effect of desiccation on lipid content, fatty acid composition and the antioxidative enzymic capacity was investigated in seeds of Telfairia occidentalis, harvested at physiological and agronomic maturity. Seeds were dried at 5 and 28 ^oC, environments that induced different drying and metabolic rates. Desiccation of seeds was associated with decreased antioxidative enzymic capacity (of peroxidase and polyphenoloxidase), and thus increased likelihood of free radical attack and decreased viability (germinability). Agronomically mature seeds contained predominantly saturated fatty acids (tridecanoic), with very low levels of the major fatty acids of edible oilseeds (palmitic, stearic or the unsaturated C18 fatty acids). There was increased accumulation of the mono-unsaturated (oleic) and polyunsaturated (linoleic) fatty acids when seeds were dried at 28 ^oC and moisture contents have reduced to about 42 % or lower. In contrast, seeds dried at 5 ^oC maintained high levels of saturated fatty acids and lower levels of monounsaturated or polyunsaturated fatty acids. Results suggest the need to develop different post-harvest protocols for seed storage, and for processing T. occidentalis to ‘improve’ the seed fatty acid profile as an oilseed for human and animal food.

Key words: Agronomic maturity, desiccation, fatty acid, lipid peroxidation, oilseed.