Supercritical fluid extraction with supercritical CO2 (SC-CO2) is applied to extract the vegetable oil from
watermelon seeds. A small face central composite design (SFCCD) is employed to optimize the extraction
parameters. The maximum value of cumulative extraction yield (CEY) for watermelon oil is found to be
about 51.83 wt%, and was obtained when SC-CO2 extraction is carried out at 60 C, 400 bar, 15 g/min solvent
flow with 10% co-solvent and with 0.50 mm particle diameter. The analysis of response surface
showed that, extracted data are adequately fitted to reduced second-order polynomial model and all
independent variables, quadratics of independent variables and some interaction parameters between
independent variables have significant effects on CEY. The correlation coefficients ‘‘R-square’’, ‘‘adjusted
R-square’’ and ‘‘predicted R-square’’ values for reduced quadratic model are 0.9974, 0.9907 and 0.9226,
respectively. The chemical composition of seed oil shows that 75.1% unsaturated and 24.9% saturated
fatty acids are present in the seed oil. Further, it is found that watermelon seed is a high source of linoleic
acid.