Purification and deodorization of structured lipids by short path distillation

Purification of structured lipids (SL), produced from lipase- catalyzed acidolysis of rapeseed oil and capric acid, and deodorization of randomized SL, produced from chemical randomization of fish oil and tricaprin, were studied in a bench-scale short path distillation (SPD). SL obtained from enzymatic acidolysis usually contain a large proportion of medium-chain and long-chain free fatty acids. Two SPD steps have been applied for the removal of free fatty acids. Parameters such as evaporator temperature, feeding flow rate, stirring roller speed, and the content of free fatty acids (FFA) added to the starting materials were optimized with respect to FFA left in the product residuals and to tocopherol loss from the starting oil. Evaporator temperature and flow rate were optimized using response surface methodology and two models were obtained for the FFA content left and loss of tocopherols. An applicable parameter zone was created to obtain a certain FFA (0.5% for example) content. In general, conditions that result in a lower FFA content will lead to a higher loss of tocopherols. In most parts of the parameter zone, 50% loss of tocopherols will be expected. The deodorization study of randomized SL from fish oils and tricaprin indicated that SPD in comparison with batch deodorization gave a product of a poorer sensoric quality