Effects of roasting on physicochemical properties and fatty acids composition of okra seed oil

Abstract

Okra is a high-yielding annual crop whose seed oil potential has yet to gather much attention compared to its seedling and regeneration purposes. This study aimed to evaluate the effects of roasting temperature (120 –200 °C) and roasting duration (10 – 40 mins) on the physicochemical properties and fatty acids of the oil extracted from okra seed. Morphological studies of grounded unroasted and roasted okra seed samples were also examined using scanning electron microscopy. Standard methods were used in determining the yield, free fatty acid (FFA), saponification value (SV), colour, and specific gravity (SG) of the extracted oil. The oil yield ranged between 22.13 and 64.27%, FFA (3.45 and 7.47), SV (174.38 and 184.80), colour (13.09 and 21.83), and SG (0.93 and 0.98), respectively. The okra seed oil from both roasted and uroasted seed showed the presence of linoleic acid (25.57 – 31.03%) and oleic acid (16.18 – 27.92%) as the primary polyunsaturated fatty acid and monounsaturated fatty acids respectively. Palmitic (6.85 19.83%) and stearic acid (3.00 5.31%) are the main saturated fatty acids in the okra seed oil. The surface of unroasted okra seed was smooth and compact, while roasting caused cell rupture of roasted okra seeds, leading to an increase in oil yield. This study provided valuable information on okra seed oil which would be of significant use for potential oil producers.