A MODIFIED METHOD FOR DETERMINING FREE FATTY-ACIDS FROM SMALL SOYBEANOIL SAMPLE SIZES

A modification of the AOCS Official Method Ca 5a-40 for determination of free fatty acids (FFA) in 0.3 to 6.0-g samples of refined and crude soybean oil is described. The modified method uses only about 10% of the weight of oil sample, alcohol volume, and alkali strength recommen ded in the Official Method. Standard solutions of refined and crude so y bean oil with FFA concentrations between 0.01 and 75% were prepared by adding known weights of oleic acid. The FFA concentrations, determi ned from small sample sizes with the modified method, were compared wi th FFA percentages determined from larger sample sizes with the Offici al Method. Relationships among determinations obtained by the modified and official methods, for both refined and crude oils, were described by linear functions. The relationship for refined soybean oil had an R-2 value of 0.997 and a slope of 0.99 +/- 0.031. The values for crude soybean oil are defined by a line with R-2 = 0.9996 and a slope of 1. 01 +/- 0.013.