A two-step process was used to produce diacylglycerol-enriched structured lipid that contained mainly c9,t11 and t10,c12 isomers of conjugated linoleic acids (CLA). First, a structured triacylglycerol (TAG) was synthesized by lipase-catalyzed acidolysis of corn oil with CLA. This structured triacylglycerol contained 30.4 mol% CLA with 45.5% of the CLA mostly located at sn-1,3 positions of the glycerol backbone. Then, lipase-catalyzed glycerolysis was conducted between structured triacylglycerol and glycerol to produce diacylglycerol-enriched structured lipid. The final product contained 6.8% monoacylglycerol, 31.5% diacylglycerol and 61.1% TAG after 48 h reaction. The selected chemical (fatty acid composition, the content of mono-, di-, and triacylglycerol in the reaction product) and physical properties (melting profile) were determined by hihg-performance liquid chromatography (HPLC), gas chromatography (GC), and differential scanning calorimetry (DSC).

Recently, dietary oil with high diacylglycerol (DAG) contents, so called DAG-oil, was introduced in Japan and the USA. It was claimed that the oil mostly composed of DAG is metabolized differently from conventional triacylglycerol oil, reducing body weight and fat mass because DAG tends to be oxidized to provide energy rather than stored as fat in the body. Monoacylglcyerol and DAG could be prepared by lipase-catalyzed reactions including hydrolysis, esterification, and glycerolysis. In this study, modified lipid containing some DAG esterified with the health-beneficial medium-chain fatty acids and conjugated linoleic acid was produced by lipase-catalyzed reactions. Many health benefits of medium-chain fatty acids (C6:0-C12:0) and conjugated linoleic acid isomers have been reported, including anticarcinogenic and antiatherogenic activities, and being rapid energy sources for humans with little or no deposition as body fat. The produced lipid molecules in this study have potential applications as functional healthy dietary fats and oils.

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Scale-up production of low-trans fat containing conjugated linoleic acid (CLA-TFO) was performed through lipase-catalyzed synthesis. Blend of fully hydrogenated soybean oil, olive oil containing conjugated linoleic acid and palm oil with 1:2:7 ratio was interesterified through Lipozyme RM IM in the 1 L-batch type reactor at 65 o C for 12 hrs, and the physicochemical and melting properties of CLA-TFO were compared with conventional (high trans fat) or commercial low-trans fat shortening. The trans fatty acids content in the conventional shortening (48.8 area%) was much higher than that of low-trans shortening (0.4 area%) and CLA-TFO (0.3 area%＋CLA; 7.6 area%). Acid, saponification and iodine values of CLA-TFO were 0.4, 173.9 and 59.0, respectively. Their α-, γ-tocopherol contents showed 4.7, 1.0 mg/100 g. Differences were observed in the solid fat contents (SFC), melting point of the conventional or low-trans fat and CLA-TFO. Each SFC of conventional, low-trans fat and CLA-TFO was 32.0, 29.3 and 30.4% with melting point of 38.5, 43.0 and 39.5 o C at 35 o C, respectively. In texture profile analysis, hardness of conventional, low-trans fat and CLA-TFO was 111.7, 75.2 and 63.8 g.