Effect of thermal treatments on immunoreactivity and proteolytic activity of papain.

Abstract

Thermal treatment of papain affects somewhat less its immunoreactivity than its proteolytic activity, especially when higher temperatures and longer heat exposures are applied. Immunochemical methods seem to be, in this respect, more advantageous for papain determination in thermally processed food samples (e.g. pasteurized beer) than assays of proteolytic activity. The proteolytic activity is substantially influenced by the type of substrate used. The following substrates affect the proteolytic activity of partly inactivated papain in an increasing order: low-molecular weight substrate BAPA (N alpha-benzoyl-D, L-arginine-p-nitroanilide) less than HPA (hide powder azure) less than hemoglobin. A protective effect of albumin on papain thermoinactivation was found using both immunochemical and proteolytic activity assays.