The use of proteases from extreme thermophiles for meat tenderisation

The potential use of the thermophile enzymes E A.1 protease (from Bacillus strain E A.1), 4-1.A protease (from Thermus strain Rt4-1.A) and caldolysin (from Thermus strain T-351) in meat tenderisation has been investigated. Temperature-activity relationships illustrated that E A.1 and 4-1.A proteases were more active on collagen than on meat powder at cooking temperatures (70-90°C), whereas caldoysin was more active on meat powder. The potential of E A.1 and 4-1.A proteases was therefore investigated further using sensory and mechanical evaluation. An Instron Universal Testing Machine was used to quantitatively investigate the effect of cooking temperature and protease concentration on homogenised meat patties. With a cooking time of 30 min, the best protease concentrations (of those used) were found to be 0·75 U/g meat for E A.1 protease and 1·5 U/g meat for 4-1.A protease. The optimum cooking temperature was 80°C in both cases. Sensory analysis confirmed that these concentrations (and also 0·38 U/g meat for E A.1 protease) improved the tenderness significantly. At high concentrations the proteases had a detrimental effect on the mouthfeel of the patties. At lower concentrations this effect was less marked, and good tenderisation was obtained.