Acceleration of Cheese Ripening with Liposomes-Entrapped Proteinase: Influence of Liposomes Net Charge

A proteolytic enzyme ~Neutrase) used for the acceleration of cheese ripening was entrapped in neutral, positively charged, or negatively charged liposomes prepared by reversed phase evaporation. The liposomes-trapped enzyme was then added to Saint-Paulin cheese milk. Ionic liposomes entrapped more enzyme than neutral liposomes. The percentage of retention of the liposomes in the cheese was highest for positively charged, then negatively charged, then neutral liposomes. Liposomes stability in milk was lower at acidic pH and also decreased with increasing temperature and NaC1 concentration. Neutral and positive liposomes were more stable than negative liposomes. Low adsorption of Neutrase on liposomes surface was observed.