DEVELOPMENT OF AN IMMUNOLOGICAL METHOD FOR STUDYING THE INCORPORATIONOF RIPENING ENZYMES IN CHEESE CURD

Polyclonal antibodies raised against partly purified aminopeptidase we re specific to cell-free extracts of Lactobacillus casei subsp. pseudo plantarum UL 137, and did not cross react with any other proteins in C heddar cheese, at least during the first week of maturation. A sandwic h enzyme-linked immunosorbent assay (ELISA) was developed in order to quantify cell-free extracts in the cheese curd, and was also used to d etermine the efficiency of encapsulation of cell-free extracts in lipo somes. This method was very sensitive and exhibited a detection limit of similar to 10 mu g total protein/g cheese and similar to 1 mu g tot al protein/ml liposome suspension. The efficiency of encapsulation of cell-free extracts into liposomes was similar to 55-60 %. The retentio n of liposome-encapsulated cell-free extracts was similar to 14 times that of non-encapsulated extracts.