Variety of Watermelon and Method of Drying Affect the Chemical and Functional Characteristics of Oils Extracted from Watermelon Seeds

Utilization of watermelon seeds as a source of oil production can help reduce the waste generated from its consumption and also provide an alternative source of domestic or industrial oil to peanut and palm nut oil in Ghana. The objective of this study was to investigate the effect of the variety and the mode of drying on some chemical and functional properties of oils extracted from the dried seeds of two varieties of watermelon (Crimson sweet and Black seeded ice cream). Seeds of the two varieties were subjected to different drying conditions (sun-drying and oven-drying) after which oils were extracted from the dried seeds using the Soxhlet apparatus. Chemical and functional properties investigated in the extracted oils were acid value/free fatty acid, saponification value, iodine value, ester value, peroxide value, water absorption capacity, emulsion stability and ability. Results of the study showed that the oil extracted from oven-dried crimson sweet had the lowest acid value, free fatty acid and saponification value. It was observed that the acid value, free fatty acid, peroxide value and saponification value are significantly affected by the drying method and to a lesser extent the variety of watermelon used. Figures obtained for the acid value, free fatty acid, saponification value and ester value of the crude oils were within the standard range for edible oils.

Keywords: chemical properties, functional properties, edible oils, sun-drying, oven-drying, watermelons, variety.