Effect of temperature programming on the performance of urea inclusion compound‐based free fatty acid fractionation

Abstract

AbstractThe effect of cooling rate on the degree of removal of saturated acyl groups from FFA derived from canola oil and the isolation of di‐ and polyunsaturated acyl groups from FFA derived from vegetable and fish oil, respectively, during urea inclusion compound (UIC)‐based fractionation was investigated. Traditionally, slow cooling has been used (ca.−1°C min−1). A more rapid cooling rate (−47°C min−1) produced UIC crystals of similar morphology and thermodynamic properties, but of a size an order of magnitude smaller than the UIC formed during slow cooling. Fractionations used only renewable materials (urea, FFA, and 95% ethanol as solvent) and benign operating conditions (ambient pressure, 25–75°C, and neutral pH). When the recovery of FFA (in the solvent‐rich phase) was relatively high (>60%), the selectivity of UIC‐based fractionation toward the inclusion of saturated FFA and against polyunsaturated FFA was not affected by the cooling rate. In contrast, when the FFA recovery was low, representing cases in which an increase of the PUFA purity is a more important economic goal, a slower cooling rate resulted in a significantly greater discrimination against PUFA groups, hence to a FFA product with a measurably greater purity.