Watermelon White Rind as a Natural Valuable Source of Phytochemicals and Multinutrients

Abstract
 
Watermelon white rind as agriculture waste posed potential pollution and ecological problems. Rind constitutes 30% of the weight of whole watermelon fruit. The present study focused on determining the antioxidant activity, fatty acid composition, mineral content, vitamins and amino acid profile of the white rind. The results revealed that the rind had total antioxidant activity of 2974±11.31 mg AAE/100g, total phenols content of 139.6±2.54 mg GAE/100g and total flavonoids of 40.4 ±0.92 mg QE/100g. Ferric reducing antioxidant power (FRAP) assay indicated the high reducing ability of the rind. Crude protein content amounted to 13.3%, crude fiber (14.7%) and fat (2.11%). Moreover, mineral analysis ensured that the rind is a source of iron (30.4 mg/kg), potassium (6.95%), copper (9.4 mg/kg), chromium (85µg/100g) and selenium (542µg/100g).  Unsaturated fatty acids amounted to 81.2%. Glutamic acid and lysine were the most predominant amino acid found in the rind. Vitamins A and E valued 383.44 µg/100g and 3.72 mg/100g, respectively. As a conclusion, watermelon white rind can be regarded as a potential source of phytochemicals and other nutrients.