Microencapsulated enzyme systems for the acceleration of cheese ripening

Abstract

Enzymes and substrates encapsulated in either milkfat-coated microcapsules or liposomes have been investigated for potential use as agents to accelerate cheese ripening. Milkfat-coated microcapsules have been used to efficiently encapsulate cell-free extracts, viable cells, purified enzymes, and spores. Encapsulation efficiency was dependent on the conditions used during capsule production. Addition of these microcapsules to cheese has resulted in increased levels of flavour compounds such as diacetyl, acetoin, methanethiol, and methyl ketones, compared to levels in control cheeses. Limitations due to cofactors have been overcome by co-encapsulating enzymes which recycle needed cofactors. Liposomes have been used to carry cell-free extracts and enzymes into cheese. Trials with different types of liposomes revealed that enzymes could be entrapped more efficiently and liposomes retained in the cheese curd better when multilammelar vesicles rather than small unilamellar vesicles or reverse phase evaporation vesicles were used. the stability of liposome preparations was found to be adversely affected by increased pH, temperature, and sodium chloride concentrations, as well as by negative surface charge. Encapsulation efficiency was found to increase by using a dehydration-rehydration procedure for liposome preparation. Temperature sensitive liposomes were investigated as a means of obtaining controlled release of the enzymes into the cheese.