Effects of Cooking on the Chemical and Phytochemical Composition of Raw and Cooked Walnut and Melon Seeds

Abstract

This study was aimed at determining the effects of cooking on proximate, phytochemical and selected vitamins composition of melon (Citrullus colocynthis) and walnut (Tetracarpidium conophorum) seeds. Walnut and melon seeds were obtained from theopen market and were divided into two half, one half subjected to boiling and oven dried while the other half was left untreated.Resultshowedhigher moisture and ether extractsin cooked melon (10.20 and 61.1%) and raw walnut (11.5 and 44.5%), while higher crude protein, crude fibre and ashwereinbothraw melon (30.78, 3.50, and 3.50%) and walnut (32.24, 4.09 and 5.38%). Higherphytate and flavonoid were in both cooked melon (0.72 and 24.22%) and walnut (0.81 and 21.13mg/100g) seeds. There were higher terpenoid, and alkaloid in both raw melon (37.02 and 5.23mg/100g) raw walnut (32.90 and 13.06mg/100g) seeds. A higher saponin (23.22mg/100g) was in raw melon seeds compared to cooked melon (19.22mg/100g) while cooked walnut had a higher saponin content (24.90mg/100g) compared with walnut (24.60mg/100g). Cooking method used resulted into areduction in vitamin A, C and D except for vitamin D in cooked walnut (0.53mg/kg) which was insignificantly higher than raw walnut (0.50mg/kg). Vitamin E was highest (69.40mg/kg) in raw walnut and raw melon seeds (3.07mg/kg) among the vitamin determined. The proximate composition of both seeds shows a rich source of nutrient and cooking could help to reduce anti-nutrients but more research would be required to determine their in-ovo dietary effects in animals.