Production of hard butter and structured lipid from coconut (Cocos nucifera L.) oil

In the single-step fractionation, acetone gave the highest yield of high melting point cocostearin. The optimum conditions for the fractionation were at 10 deg C, 6 hr and with an acetone - CNO ratio of 2:1 (v/v). In the multi-step procedure, the melting point (30.6 deg C), hardness, and supercooling properties of cocostearin 3 produced were comparable to cocoa butter due to enrichment of long chain fatty acids in the first step, and medium chain fatty acids in the last step. On the other hand, the fatty acid profile of coco-olein 3 was comparable to CNO. Study of sodium methylate-catalyzed transesterification suggested that transesterification below 60 deg C was optimum in the solvent-free system with substate preheating at 60 deg C for 15 min, and at 4% wet sodium methylate. The transesterification was not a random transesterification as indicated by differences of interesterification degree of the native acyls to that of donor acyl. Hard butter preparation was recommended at 50 deg C for 3 hr. The optimum condition for acidolysis of CNO and palmitic/stearic acid (2:1 w/w) in n-hexane, catalyzed by either Lipozyme M IM (LIM) or Rhizopus delemar Lipase (RDL), required 10% water content of enzyme and , a 10% enzyme load. LIM retained its interesterification activity within 40-60 deg C. RDL showed optimum activity at 45 deg C. At these optimum conditions, the acidolysis of CNO reached equilibrium at 18 hr, exhibited 1,3-regiospecificity. The hard butter produced had a melting point of 32.4 deg C and 38.7 deg C, in the RDL- and LIM- catalyzed system, respectively. Two substrate systems (CNO/PST and Cocostearin/PST; PST= palm stearin) were transesterified. In chemical transesterification, the maximum yield was obtained at a CST-PST ratio of 1:1. In lipase-catalyzed interesterification, CNO-PST (ratio of 1:1) was the best substrate because it produced hard butter that had melting points of 32.8 and 33.4 deg C, as well as yields of 72.3% and 76.4%, for LIM- and RDL- catalyzed acidolysis, respectively. For structured liquid preparation, coco-olein and soybean oil (3:1) was transesterified. The lipase-catalyzed transesterification produced SL with lower yield and melting point, but a higher iodine value and unsaturated fatty acid content than that SL from chemically catalyzed transesterification. Lipase-catalyzed transesterification was superior to chemical interesterification and suitable for use as salad oil because the SL produced remained clear if stored at 15 deg C for 5 hr