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A modified method for determining free fatty acids from small soybean oil sample sizes
Author(s) -
Rukunudin I. H.,
White P. J.,
Bern C. J.,
Bailey T. B.
Publication year - 1998
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-998-0066-z
Subject(s) - soybean oil , oleic acid , chemistry , chromatography , alcohol , acid value , linear relationship , mathematics , crude oil , fatty acid , sample (material) , food science , organic chemistry , statistics , biochemistry , petroleum engineering , engineering
Abstract 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 recommended in the Official Method. Standard solutions of refined and crude soybean oil with FFA concentrations between 0.01 and 75% were prepared by adding known weights of oleic acid. The FFA concentrations, determined from small sample sizes with the modified method, were compared with FFA percentages determined from larger sample sizes with the Official 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.