The effect of roasting process on the oxidation of watermelon oil

In this study, some chemical compounds of watermelon seeds, consumed as a snack, supplied from Mardin, Diyarbakır and Batman were determined. In addition, the effects of different roasting temperatures (140, 160 and 180°C) during 60 min on the oxidative stability of watermelon oil were investigated in watermelon seeds obtained from Diyarbakır and Batman. It was determined that the content of dry matter, ash, oil, protein, crude cellulose, total tocopherol and total phenolics of watermelon seeds varied between 95.39 and 95.58%, 3.10 and 3.38%, 51.65 and 52.75%, 32.76 and 34.87%, 17.75 and 27.85%, 360.12 and 393.16 mg/kg, 427.75 and 478.80 mg GAeq./kg oil-free, respectively. The fatty acid composition of watermelon seeds showed that, it is an important source of linoleic acid (59.89-60.74%) which is an essential fatty acid and contains a high amount of oleic acid (19.75-20.48%). It was concluded that the roasting process did not affect the fatty acid composition of watermelon seeds. The peroxide values slightly changed in the samples of Batman and Diyarbakır varied between 1.57-3.0 meq O2/kg oil and 1.54-3.23 meq O2/kg oil, respectively. On the contrary, the effect of roasting temperature on the peroxide values of the samples was found statistically significant (p <0.05). The values of K232 ranged from 2.54 to 4.01 during roasting in the samples obtained from Batman and ranged from 3.19 to 4.36 in samples provided from Diyarbakır. The K232 and K270 values of the samples roasted at 180 ° C were statistically different from those roasted at 140°C and 160°C, except for K232 values of the samples obtained from Diyarbakır (p<0.05). As a result of the study, it was determined that watermelon seeds contained significant amounts of linoleic acid, the essential fatty acid, and that the roasting process causes small changes in the oil oxidation parameters.