The effect of chemical refining process on the physicochemical and fatty acid composition of water melon seed oil (Citrulus lanatus L.)

A lot of watermelon seed waste is wasted, generally its only used to make "kuaci", a kind of salted saline a snack made from watermelon seeds. As a member of Cucurbitaceae family, watermelon seeds can be used as a source of vegetable oil that predicted contains squalene inside like other Cucurbitaceae members. This study aims to determine the effect of refining process on the physicochemical properties and composition watermelon seed oil. Watermelon seed oil which is obtained by using Soxhlet extractor in n-hexane solvent was refined in 3 steps, which was degumming, neutralization, and bleaching, respectively. Degumming process used 3 concentrations of H3PO4, which were 0,15%; 0,20%; and 0,25%, respectively; whereas 3 zeolit concentrations of 2%; 4%; and 8%, respectively were used in bleaching steps. Data were analyzed by using 3x3 Factorial design and it was laid out with Randomized Completely Block Design, 3 replications and as the block is time analysis. The optimum yield of the watermelon (C. lanatus L.) seed oil is obtained in the amount of 48.47 +/- 0.91 % at 0.25% phosphoric acid concentration and 4% Zeolite concentration. The result of physicochemical analysis before and after the refining process have changed. The density, peroxide value and acid value show a significantly decrease, while only the saponification value shows an increase. Fatty acid composition (profile) of WSO before and after refining process does not change, comprises linoleic acid, palmitic acid, stearic acid and squalene (unsaturated hydrocarbon). Linoleic acid is the main compound of WSO (76.69%), followed by palmitic acid (14.60%), stearic acid (6.53%) and squalene (2.18%), respectively.