Acidolysis to incorporate oleic acid into refined, bleached and deodorized (RBD) palm olein (IV 56) using various lipases (enzymes) as catalysts to increase the oleic content of the oil was investigated. Immobilised lipases (lipase PLG, Lipozyme TL IM, Lipozyme RM IM and Novozym 435) and non-immobilised lipase (lipase PL) were used in this study to compare the effectiveness of the selected lipases in catalyzing the reaction to produce a high oleic oil. The results showed that the TAG of OLO/OOL content was increased at least 4 fold and OOO content was increased at least 3 fold when a 5% enzyme load was used. Lipase PL showed the greatest increase in tri-unsaturated triacylglycerols (TAGs) content. A pilot scale experiment conducted using TL IM enzyme, followed by recovery of the oil and fractionation allows the production of oils with varying oleic contents. A high oleic content of 56% was achievable.
The lipase-catalyzed interesterification of refined, bleached, deodorized palm olein with iodine value (IV) of 62 was studied in a pilot continuous packed-bed reactor operating at 65 degrees C. Sn-1,3 specific immobilized enzyme; Lipozyme TL IM (Thermomyces Lanuginosa) from Novozyme A/S was used in this study. The interesterification reaction produced fully solidified fats at ambient temperature due to the production of trisaturated triacylglycerols (TAG) (PPP and PPS, where P = palmitic acid, S = stearic acid). The reaction also increased the percentage of triunsaturated TAG (OLL, OLO, and OOO, where O = oleic acid, L = linoleic acid). The interesterified product was then dry fractionated at temperatures of 9, 12, 15, 18, and 21 degrees C to separate the saturated fats from the unsaturated. The results show that IV of olein increased when the fractionation temperature (T(FN)) decreased. The highest IV of olein was 72, obtained from T(FN) at 9 degrees C. After interesterification and laboratory-scale fractionation, the olein fractions contained higher unsaturation content ranging from 64.7% to 67.7% compared to the starting material (58.3%), while the saturation content was reduced from 41.7% to the range of 32.3% to 35.3%. The yields of these oleins were low with the range of 24.8% to 51.8% due to the limitation of the vacuum filtration. Ten kilograms of pilot-scale fractionation with membrane press filter was used to determine the exact olein yield. At T(FN) of 12 degrees C, 67.1% of olein with saturation content of 33.9% was obtained.