PROTEASES IN FRESH PORK MUSCLE AND THEIR INFLUENCE ON BITTER TASTE FORMATION IN DRY-CURED HAM

Abstract

Legs from 10–12 month old heavy pigs were assayed for cathepsin B and peptidase activities, and dry-cured following regulatory standard procedures. Dried hams were analyzed for proximate muscle (biceps femoris) composition, free amino acids (FAA), enzyme activities and perception of bitter taste by a trained sensory panel. Protein breakdown, measured by nonprotein nitrogen (NPN), and FAA content were greater in the more bitter samples, as were cathepsin B and dipeptidyl (DPP I and DPP II) activities. In contrast, hams with null or mild bitter intensity exhibited higher aminopeptidase activities in both the fresh and aged muscle. A distinct FAA pattern was found for each class with the bitter hams being abundant in methionine, asparagine and isoleucine and less rich in tyrosine, arginine and ornithine.