Part 2: Designer Enzyme Tenderisers

Summary

Several plants and microbial enzyme preparations have been researched to determine whether the exogenous application of proteases can reliably tenderise meat. Successful use of these enzymes in fresh meat requires their enzymatic kinetics and characteristics to be determined, together with an understanding of the impact of the surrounding environmental conditions (pH, temperature, release and accumulation of metabolites during meat storage) on enzyme function. This enables the optimal conditions for tenderising fresh meat to be established, and the elimination or reduction of any negative impacts on other quality attributes.  
These projects investigated and characterised the activity of seven commercial proteases (papain, bromelain, zingibain, actinidin, bacterial protease G, fungal 31K and fungal 60k) sourced from Australian suppliers, and two in-house preparations (Kiwifruit and Asparagus extracts) using synthetic substrates (BODIPY-casein, CBZ-Lys-p-nitrophenol and Azocoll) and meat protein fractions (myofibrils, collagen and elastin). Furthermore, the effect of some commonly used additives on the proteolytic activity of the enzymes was investigated using meat myofibrils. The effects of the commercial enzyme preparations (when applied according to the manufacturers’ recommendations), and the two in-house preparations on the eating and keeping qualities and the protein degradation in the sarcoplasmic and myofibrillar fractions of hot-boned topside (M. semimembranosus) from cull dairy cows was also investigated.