Enzymatically catalyzed synthesis of anti-blooming agent 1,3-dibehenoyl-2-oleoyl glycerol in a solvent-free system: optimization by response surface methodology.

Products rich in 1,3-dibehenoyl-2-oleoyl glycerol (BOB) triglyceride (TAG) were produced by enzymatic interesterification of high oleic acid sunflower oil (HOSO) and behenic acid methyl ester (BME) by 1,3-regiospecific lipase Lipozyme RM IM in a solvent-free system. The impact factors of enzyme load, substrate molar ratio of BME to HOSO (BME/HOSO), reaction time, reaction temperature, and pre-equilibration water activity of the enzyme on BOB content and BME conversions were investigated by single-factor experiments and then optimized using the response surface methodology (RSM). The optimum conditions were as follows: reaction temperature, 72 °C; reaction time, 7.99 h; substrate molar ratio, 2.5:1; enzyme load, 10%; and pre-equilibration water activities of the enzyme, 0.28. The results from the experiments conducted according to the predicted optimal conditions were as follows: the content of BOB was 32.76%, and the conversion of BME was 65.16%. The experimental values agreed with the predicted values, which verified the sufficiency of the quadratic regression models. After purification under the optimal short-range molecular distillation and two-step solvent fractionation, the content of BOB in the target product can reach 77.14%, indicating the great potential for industrial production of the anti-blooming agent.