Rapid and complete extraction of free fatty acids from oilseeds for acid value determination

The rapidity and uncertainty of the acid value determination in oilseeds are defined by the rate and completeness of the free fatty acid extraction. The strategy of reagent development for extraction has been discussed, and a set of reagents that provide rapid and complete extraction has been obtained. The set consists of two reagents. Reagent A contains triethanolamine in a mixture of water, isopropanol, and heptane. Reagent B contains a strong acid and inorganic salt in water. Reagent A allows the carrying out of rapid (1–2 min) solid-liquid extraction of the free fatty acids and some other acids from oilseeds. Reagent B provides the separation of the free fatty acids only into the heptane phase (∼5 min), which can be used directly for the free fatty acid determination. Two techniques for this determination have been applied: pH-metric and titrimetric. The advantages of the proposed set of reagents are described.