Deacidification of Crude Hazelnut Oil Using Molecular Distillation - Multiobjective Optimization for Free Fatty Acids and Tocopherol

Hazelnut oil is a good source for its high oleic acid and tocopherol contents. Since tocopherols are beneficial compounds in human diet, preservation of tocopherols in oil plays a great role in refining process. The aim of this study is to determine the optimum molecular distillation conditions for deacidification of crude hazelnut oil at which free fatty acids (FFAs) are removed while tocopherols are preserved as much as possible. A short-path distillation column is used with evaporation temperatures ranging from 110 to 190 degrees C and vacuums from 0.05 to 5mmHg for deacidification. Multiobjective optimization is performed for minimizing tocopherol loss and maximizing FFA removal simultaneously. Results reveal that higher temperature and vacuums achieve more deacidification in residual oil. FFA content is reduced to 2.05% at 190 degrees C and 0.05 mmHg. On the other hand, tocopherol concentrations are considerably affected at this condition while they remain almost stable at other conditions. Optimized conditions for removal of FFAs and protecting of tocopherols in crude hazelnut oil are calculated as 188.65 degrees C and 0.14 mmHg. For verification, an additional distillation is carried out at the calculated conditions, and the results are found very close to that of optimized conditions.