COMPARISON OF THE NUTRITIONAL AND PHYSIOCHEMICAL PROPERTIES OF THE PULP AND SEED OIL OF PAWPAW AND WATERMELON

Abstract

The nutritional composition, antioxidant activity and polyphenol oxidase activity of watermelon and pawpaw pulp was studied, and the physiochemical properties of the oil extracted from both seed was determined. The activities of several antioxidants were tested, including the Total Phenolic Content (TPC), Total Flavonoid Content (TFC), Ferric Reducing Antioxidant Power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH). The proximate composition in term of moisture, ash,crude fibre, protein and carbohydrate were determined. The moisture, ash content, crude protein, fat , crude fibre and carbohydrate by differences were found to be 88.50 %, 0.91 %, 0.57 %, 0.14 %, 0.89 % and 8.99 % for the pawpaw pulp and 92.82 %, 0.79 %, 0.46 %, 0.20 %, 0.15 % and 5.69 % for the watermelon pulp respectively. The pawpaw pulp showed a high antioxidant activity in terms of TPC, TFC, FRAP, DPPH when compared to the watermelon while the watermelon pulp shows a high polyphenol oxidase activity (49.1 s-¹mg-¹) than the pawpaw pulp (14.5 s-¹mg-¹). The physiochemical properties of the extracted oil from the seed shows that watermelon seed has a higher saponification, acid value, iodine value and density with values corresponding to 179.25 mgKOH/100g, 2.58 mgKOH/g, 128.82 meq/kg and 0.81g/cm³ when compared to the pawpaw seed with values corresponding to 95.70 mgKOH/100g, 2.48 mgKOH/g, 76.26 meq/kg and 0.68 g/cm³ respectively.