Temperature Sensitivity and Pressure Resistance of Mushroom Polyphenoloxidase

Measurements of residual enzyme activity and FTIR‐spectroscopy revealed that mushroom polyphenoloxidase is a thermosensitive enzyme readily inactivated by temperatures exceeding 50°C. The enzyme is, however, very pressure stable. At room temperature no enzyme inactivation occurred at pressures up to 6 kbar. FTIR‐spectroscopy revealed that a modification in enzyme conformation occurred below 9 kbar. Kinetic studies showed that pressure and temperature did not always act synergistically with respect to enzyme inactivation. FTIR‐spectroscopy showed that pressure‐ or temperature‐induced changes were considerably different. Both temperature and pressure‐temperature inactivation were only slightly influenced by pH (in the pH‐range 5.5–7.5).