Detection of Myristic and Palmitic Acid in Butter By Hydrolysis And Acid Methylation

Abstract

Abstract Myristic acid and palmitic acid in butter was successfully detected by Gas Chromatography Flame Ionization Detector (GC-FID) after hydrolysis and methylated to fatty acid methyl esters (FAMEs). Optimization of initial oven temperature and carrier gas flow rate were determined earlier, and it was found that 50°C and 2.0 mL/min were chosen as optimum initial oven temperature and carrier gas flow rate respectively. Two different calibration curves were constructed using methyl myristate and methyl palmitate. Both were found linear at 20-100 ppm with correlation coefficient (R2) 0.9972 and 0.9933 respectively. Methyl stearate were used as an internal standard (IS). Limit of detection (LOD) where the lowest concentration that can be detected by the instrument was found at 16 ppm. In order to determine the concentration of FAMEs in butter, fatty acids were hydrolyzed using lipase enzymes and were converted to FAMEs by acid catalyst methylation method. Butter with Brand A, B and C was found to contain 24 ppm, 21 ppm and 30 ppm Methyl Myristate. Methyl Palmitate was only found in butter Brand B and not detected for another two brands.