A Novel Modified Lipid: Enzymatic Esterification of 2-Monoacylglycerol with N-acetyl-l-leucine.

The objective of this research was to synthesize and characterize a novel modified lipid which is composed of mainly oleic acid at sn-2 position and a hydrophobic essential amino acid derivative (N-acetyl-l-leucine) at sn-1(3) or sn-1, 3 positions. LC-MS-MS analysis indicated that the target modified lipid structure was obtained at the end of the developed reaction. Response surface methodology was applied to enhance a reliable empirical model for prediction and to optimize reaction conditions: reaction time (8 to 24 hr), reaction temperature (40 to 55 °C), and enzyme load (15 to 30 wt%). The percentage of total reaction products was found to be 28.5 at the optimum conditions of 54 °C, 8 hr and 15% (by mass) enzyme load. This result is closely correlated to the predicted highest total reaction product (29.3%) obtained by response surface methodology. The physical and thermal characteristics of the modified lipid and refined olive pomace oil were compared and found to be similar. Caloric value of modified lipid was decreased by 18.65% compared to that of refined olive pomace oil. A novel modified lipid which may have potential uses in healthy food industries was successfully produced with the incorporation of N-acetyl-l-leucine to 2-monoacylglycerol. PRACTICAL APPLICATION: A novel modified lipid was synthesized by enzymatic incorporation of a "hydrophobic and essential amino acid derivative" into 2-monoacylglycerol. This modified lipid contains mainly oleic acid at sn-2 position and N-acetyl-l-leucine at sn-1,3 positions. The product behaved as an oil above 10 °C. Caloric value of the novel oil-like product was reduced by 18.65%. The modified lipid may have the potential for replacement with the oil in food products such as margarine, shortenings, salad dressing, and mayonnaise.