Encapsulation of a Lactic Acid Bacteria Cell-Free Extract in Liposomes and Use in Cheddar Cheese Ripening

Abstract

A concentrated form of cell free extract (CFE) derived from attenuated Lactococcus lactis supsb. lactis 303 CFE was encapsulated in liposomes prepared from two different proliposome preparations (Prolipo Duo and Prolipo S) using microfluidization. Entrapment efficiencies of 19.7 % (Prolipo S) and 14.0 % (Prolipo Duo) were achieved and the preparations mixed in the ratio 4 (Prolipo Duo):1 (Prolipo S). Cheddar cheese trials were undertaken evaluating the performance of CFE entrapped in liposomes, empty liposomes and free CFE in comparison to a control cheese without any CFE or liposomes. Identical volumes of liposome and amounts of CFE were used in triplicate trials. The inclusion of liposomes did not adversely impact on cheese composition water activity, or microbiology. Entrapment of CFE in liposomes reduced loss of CFE to the whey. No significant differences were evident in proteolysis or expressed PepX activity during ripening in comparison to the cheeses containing free CFE, empty liposomes or the control, as the liposomes did not degrade during ripening. This result highlights the potential of liposomes to minimize losses of encapsulated enzymes into the whey during cheese production but also highlights the need to optimize the hydrophobicity, zeta potential, size and composition of the liposomes to maximize their use as vectors for enzyme addition in cheese to augment ripening.