Effect of free and encapsulated recombinant aminopeptidase on proteolytic indices and sensory characteristics of Cheddar cheese

The recombinant aminopeptidase of Lactobacillus rhamnosus S93 in free or encapsulated form was used in production of Cheddar cheese. The effects of these enzymes on the proteolytic indices as well as sensory characteristics have been investigated during Cheddar cheese ripening. An extrusion method was used to encapsulate the enzyme in alginate beads coated with chitosan. The free or encapsulated aminopeptidase were added at the renneting or salting stage at three different concentrations (50, 500, 2000 units per 18 L of milk). Indices of secondary proteolysis were enhanced by increasing the enzyme concentration. Cheeses with the highest concentration of the encapsulated enzyme had significantly higher concentrations of soluble nitrogen in phosphotungstic acid and total free amino acids and received the highest mean scores for the sensory characteristics.