pH-metric determination of acid values in oilseeds without titration

A new pH-metric method for determination of acid values in oilseeds without titration has been developed in the range 0.6-10 and more mg KOH/g. The method is based on a rapid (1-2 min) selective and complete extraction of free fatty acids from an oilseed test portion into a special reagent A, separation of the solution from the solid oilseed material by centrifugation or filtration, transfer of an aliquot of the solution into a pH-metric cell with reagent B for measurement of conditional pH(1)' of the formed mixture, addition of standard acid (HCl or H2SO4) and pH(2)(') measurement. The reagents are non-toxic, and the method is rapid. Its metrological parameters for Soybean, Canola and Sunflower oilseeds are satisfactory for practical purposes. (C) 1999 Elsevier Science B.V. All rights reserved.