摘要：Vegetable oils are generally subjected to processes called as fat modification techniques which are applied to increase the area of use by altering their physical and chemical properties. Hydrogenation; being the oldest and most widely used fat modification technique; involves the addition of a hydrogen molecule to double bonds of unsaturated fatty acids. Hydrogenation is a heterogeneous, catalytic and exothermic reaction and the course of hydrogenation is evaluated by considering reaction rate, Linoleic selectivity and isomerisation. In this study; refined cottonseed oil is hydrogenated in a batch reactor at temperatures of 120°C, 150°C, and 170°C with nickel catalyst. Refractive index, fatty acid composition, melting point, and solid fat content of the hydrogenated fat are determined. iodine value and Linoleic selectivity are calculated by using fatty acid composition data. The results showed that hydrogenation yields in a linear decrease in iodine value and refractive index of the fat as the reaction proceeds. Moreover; the polyenes are converted to monoenes; and an increase is observed in the saturated fatty acid content of the product. Increasing process temperature resulted in an increased hydrogenation selectivity due to a limited increase in saturated fatty acids. But this also resulted in an increased trans isomer content which yields in a sharp and large-scaled solid fat curve (20 °C, 30 °C and 35 oC) together with a decreased melting point in the hydrogenated fats.
