Evaluating endogenous protease of salting exudates during the salting process of Jinhua ham

Strategies are being pursued with the aim of reducing salt content of dry-cured ham. To evaluate the effect of salting on protease activities, sixteen hams were randomly assigned into two groups (LS group and HS group), and two different levels of NaCl were used to dry-cure green ham. The LS group of 8 hams were salted with 6% salt (w/w), whereas the HS group of 8 hams were salted with 8% salt. The exudates were collected separately at 1, 2 and 7 d of the salting stage. The activities and contents of protease in the exudates were investigated. The intense activities of calpains, cathepsin B and L were observed at 1, 2 and 7 d of salting stage in both LS and HS group. The increased contents of 80 and 76 kDa fragments implied that there was a dramatic release of calpain from ham tissues; lower release rates of cathepsin B and cathepsin L led to high residues in LS group, which may be responsible for the intense degradation of proteins and flavor development of dry-cured ham. This paper provides new insights into the study of biochemical changes of Jinhua ham induced by endogenous protease during the salting stage.