THE PROPERTIES OF SEED OIL AND PROTEIN OF THREE UNDERUTILIZED EDIBLE CUCURBITACEAE OF SOUTHWEST NIGERIA

The indigenous cucurbitaceous species provide ready and cheap sources of leafy vegetables for the financially poor rural people of Southwest (SW) Nigeria. These species, which include Trichosanthes cucumerina, Cucurbita pepo, and Luffa aegyptiaca, also produce seeds that are used in several soup and sauce preparations in SW Nigeria. The detailed characteristics of the seed oils and proteins have not been reported in literature. Therefore, the nutritional values of the oils and proteins of the three species were studied. Analytical results showed that the oil contents were 51.2, 50.4, and 54.2 g/100 g seed while the bulk of the oils in three species was composed of linoleic acid (60.1-66.3%), oleic acid (18.7-22.5%), and palmitic acid (10.1-13.6%). Other detectable fatty acids, including myristic acid, palmitoleic acid, stearic acid, and linolenic acid, were present in the range of 0.1 to 2.6%. The saponification values were 195.6, 210.4, and 206.3 mg of KOH/g of oil while the iodine values of the oils were 127.3, 110.4, and 100.2 g of I/100 g oil for T. cucumerina, C. pepo, and L. aegyptiaca, respectively. The peroxide values of the oils were 2.9, 3.2, and 3.6 mequivalent of oxygen/kg of oil for T. cucumerina, C. pepo, and L. aegyptiaca, respectively. The protein contents for T. cucumerina, C. pepo, and L. aegyptiaca were 27.2, 25.3, and 30.4%, respectively. The essential amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) constituted a total of 41.2, 37.6, and 35.8 g/16 g of N while the semi-essential amino acids (arginine and histidine) constituted 21.6, 22.4, and 16.3 g/16 g of N for T. cucumerina, C. pepo, and L. aegyptiaca, respectively. The nutritional significance of these results for the health of humans is discussed. The paper also proposes possible industrial exploitation of the good qualities of the seed of the three species.