Improved Methyl Esterification for GC Fatty Acid Determination in Fats and Oils: Collaborative Group Study by the Working Group (Fatty Acid Derivative Subcommittee) Japan Oil Chemists’ Society

Abstract

An eight-Japanese laboratory collaborative study was undertaken to devise an improved safe rapid means for methyl-esterification (with potassium hydroxide-methanol as the reaction solution) for GC fatty acid determination in fats and oils. This group effort (Fatty Acid Derivative Subcommittee) was undertaken at the request of the Japan Oil Chemists’ Society. Optimal determination was initially made of parameters such as concentration and volume of the reaction solution and reaction period. By 0.2 mL 2 M potassium hydroxide-methanol as reaction solution, 98.6-102% recovery was confirmed in methyl-esterification for five kinds of triacylglycerol standards; tricaprylin, trilaurin, tripalmitin, tristearin, and triolein. Collaborative study with 8 laboratories on GC with coconut, lard, soybean, and palm oil by means of the fixed reaction conditions was carried out. Reproducibility coefficient of variation (CV_R) ranged from 0.6 to 2.8% for major fatty acids with peak area ratio exceeding 10% and 1.6 to 9.6% for minor fatty acids with peak area ratio less than 10%. The present method was found to qualify tentatively as the official method of the Japan Oil Chemists’ Society.