Mass transfer modeling of sardine oil polyunsaturated fatty acid (PUFA) concentration by low temperature crystallization

Low temperature crystallization of oil is employed in the production of omega-3 which are a product of interest in the food industry. The aim of this work was to model the influence of temperature and time in the mass of the solid and liquid phases. The model developed enabled the estimation of polyunsaturated fatty acids (PUFA), eicosapentaenoic acid and docosahexaenoic acids (EPA and DHA) contents in the liquid phase. Solutions of sardine oil in hexane were crystallized at several temperatures (−55, −65, −75 and −85 °C) and times (1-24 h). The transient variation of liquid phase mass at a given temperature was modeled employing two parameters: the equilibrium mass of the phase (meq, g) and the overall mass transfer coefficient (KG·A, h−1). The results showed that the highest PUFA concentrates (>80%) were produced at −85 °C and 24 h. The model proposed is a useful tool for estimating the composition and total mass of winterized oils (r2 > 0.83).