Judul: Sintesis Lipida Terstruktur Tipe Medium-Long-Medium (MLM-SL) dengan Interesterifikasi Enzimatis dari Produk Minyak Sawit
Abstrak: Medium-long-medium structured lipid (MLM-SL) is a lipid with a specific arrangement of fatty acid at which medium chain fatty acids (MCFA/C6-C12) located at sn-1,3 positions and long chain fatty acids (LCFA/C14-C24) at sn-2 position. LCFA located at sn-1,3 positions show a low absorption coefficient due to their possibilities to react with calcium to produce calcium soap. Whereas, MCFA located at sn-1,3 position is easier to be hydrolyzed by the pancreatic lipase and have a little tendency to accumulate in adipose tissue. This indicates the combination of MCFA and LCFA on same triacylglycerol (TAG) molecule is very potential to be developed due to their nutritional benefits such as reduced calorie lipid, controlling obesity, and improve fat malabsorption. The primary objective of this study was to synthesize MLM-SL using palm oil products (palm olein and palm kernel oil) as substrates in batch and continuous system. To achieve the aforementioned primary objectives, this research was carried out through five main stages: (1) determining characteristics of substrates and blended substrates for MLM-SL synthesis; (2) selection of the suited reaction type for MLM-SL (between acidolysis and transesterification); (3) determination of the Lipozyme TL IM stability during acidolysis and transesterification of MLM-SL; (4) investigating the optimum reaction condition in batch and continuous system; (5) characterization of thermal properties of MLM-SL product. This dissertation is arranged to follow the stages of the research. In the first chapter, the comprehensive review about MLM-SL is reported to give recent updates on the MLM-SL synthesis through enzymatic reaction. The second chapter discusses about the suited reaction method (acidolysis or transesterification) for MLM-SL synthesis. In addition, this chapter also explains the stability of Lipozyme TL IM during MLM-SL synthesis. The third chapter disclose the MLM-SL synthesis in continuous operation using the suited reaction type previously determined. Moreover, the effect of enzyme loading and the information of productivity are provided as well. The last chapter describes the synthesis of MLM-SL using PKO as the alternative substrate for MCFA source. MLM synthesis was carried out in batch and continuous operation to determine the effect of substrate mol ratio, reaction time, and residence time. The results showed that palm olein-tricaprylin (transesterification) and palm olein - caprylic acid (acidolysis) were potentially to produce MLM-SL, especially 1,3-dicapryloyl-2-oleoyl-sn-glycerol (COC/ECN32). In general, new triacylglycerol (TAG) species was produced after acidolysis and transesterification reaction as compared to that their blended products. In batch-wise, transesterification reaction required a shorter reaction time (2-4 h) to produce high concentration of MLM-SL than that of acidolysis reaction (20 h). Moreover, Lipozyme TL IM shows better stability in the transesterification reaction as compared to that of acidolysis reaction. In continuous systems, 15 min of residence time and 2 g of enzyme loading were selected as optimal conditions of transesterification reaction due to their high concentration of MLM-SL and lower by-products (diacylglycerol/DAG, monoacylglycerol/MAG, free fatty acid/FFA, and glycerol). In addition, transesterification reaction between palm olein and palm kernel oil (PKO) was potentially to produce MLM-SL, especially 1,3-dilauryl-2-oleoyl-sn-glycerol (LaOLA/ECN40). In general, the increasing residence time or reaction time affects the possibility of producing higher by-products. Moreover, slip melting
Keyword: acidolysis, lipase, palm oil, structured lipid, transesterification