In Situ Enzymatic Synthesis of Polar Lipid Emulsifiers in the Preparation and Stabilisation of Aerated Food Emulsions

We report on the direct incorporation of a lipase derived from Rhizomucor miehei, into aeratable food emulsion formulations, with the objective of enzymatically generating polar lipid fractions during processing, and which are able to demonstrate equivalent functionality to chemically synthesised monoglycerides. Findings showed that the lipolysis of palm oil-in-water emulsions produced a combination of predominantly oleic monoglyceride and palmitic fatty acid fractions. The extent of hydrolysis was able to be controlled through concentration of enzyme, reaction time, and reaction temperature. Hydrolysis was terminated via inactivation of the enzyme through high heat treatment of emulsions. Emulsion properties, notably stability under shear, were seen to be highly dependent on the extent of lipolysis. When applied to model whipping and ice cream formulations, lipolytic generation of polar lipids was shown to promote both partial coalescence and fat globule adsorption to bubble surfaces, generating structures equivalent to those produced by use of commercial emulsifiers. Product properties, such as physical stability and material properties showed variation according to the extent of lipolysis. Our results demonstrated that enzymatic lipolysis of emulsions under controlled conditions could be optimised to deliver requisite droplet functionality for the structuring and stabilisation of aerated food emulsions. Findings are of significance, not only when considering the potential for replacement of chemically derived emulsifiers in such formulations, but also from the perspective that this approach can readily be incorporated into existing manufacturing process operations.