with acyl donors and passes to the second stage packed-bed reactor. The second stage
product was purified by distillation and further fractionated to separate original sub-
strate oils or diacylglycerols formed. A final refining, including bleaching and deo-
dorization, was conducted to make the product suitable for edible purposes.
Another two-stage process was developed on laboratory scale for the production
of structured triacylglycerols; alcoholysis was the first step, and esterification the
second step (Schmid et al., 1998; Soumanou et al., 1998a,b; 1999). The first step
was a reaction between substrate oils and ethanol catalyzed by a lipase to produce
monoacylglycerols in the solvent system. The reaction mixture in the solvent was
crystallized and fractionated at low temperature. The monoacylglycerols were then
separated from the system and further reacted with required fatty acids in the solvent
medium. This process was reported to be suitable for the production of high-purity
product. Monoacylglycerols, however, are very unstable even at room temperature.
Acyl migration might occur and lead to the formation of different isomers (bypro-
ducts), especially when the process is scaled-up as the heat transfer and mass transfer
would be different from those in flasks. Therefore, careful reaction control might be
required and precise parameters should be obtained through process optimization.
For the production of SSL in large scale for nutritional applications, a process
using the PBR was built in the pilot plant with the capacity of 10 kg per day
11.8 Processes for the modification of oils and fats via enzymatic interesterification 211
Figure 11. Industrial process for the production of cocoa butter equivalents (CBE) and Betapol via
lipase-catalyzed interesterification using packed-bed reactors. For CBE production, high oleic sunflower
oil was used as the substrate oil and stearic acid as the acyl donor. For Betapol production, palm stearin
was used as the substrate oil and high oleic sunflower oil fatty acids as the acyl donors. (Adapted from
Quinlan and Moore, 1993; Rozendaal and Macrae, 1997.)