Supercritical Reduction of Lauric Acid in Palm Kernel Oil (PKO) to Produce Cocoa Butter Equivalent (CBE) Fat

Abstract

The extraction of dehulled ground palm kernel using supercritical carbon dioxide (SC-CO₂) as a solvent at a temperature of 40°C and pressures range from 34.5 to 48.3 MPa was studied. At 48.3 MPa and 40°C the solubility of oil was about 21.1 g/100 g carbon dioxide, however maintaining constant temperature of 40°C the solubility of oil increased with pressure. The fatty acid composition of oil extracted varied with fraction time. The first fraction had 52.2 percent lauric acid content. The lauric acid content decreased to 34.3 percent in the third fraction with an increase to more than 40 percent fatty acid with 16 carbons or more. The breakdown was 0.1 percent palmitic acid (C16), 8.9 percent stearic acid (C18:0), 20 percent oleic acid (C18:1) and 4 percent linoleic acid (C18:2). Blending of palm oil (PO), palm kernel oil (PKO), stearic acid (C18:0) and oleic acid (C18:1) at different ratios were carried out to obtain blends as cocoa butter replacers (CBR) fat. The lauric and myristic acids were reduced to 9.03 and 4.44 percent in the CBE blend, although there are no lauric and a trace of myristic acid in CB. The percentages of other fatty acids in CBE were found to correlate well to the CB except C18:0 which was only 16.15 percent. The slip melting point (SMP) increased with the increase in C18:0. The value of SMP was found to be 36.1°C for the CBE blend whereas for the CB it is 35°C. The iodine value for the CBE blend was found 38.3 where as for CB it is 36. The solid fat content (SFC) of CBE at 20, 35 and 37.5°C was found to be 59.3, 8.5 and 0 percent, respectively. Whereas, the SFC values of CB are 72, 11 and 0 percent, respectively. Although the percent of the C18:0 in the CBE was lower than the commercial CB but it did not affect to the SMP and SFC.