Enzyme sensitivity towards high pressure at low temperature

Abstract

The sensitivity of several selected enzymes, e.g. Bacillus subtilis α‐amylase (BSA), peroxidase (POD), pectinmethylesterase (PME), polyphenoloxidase (PPO) and lipoxygenase (LOX) towards the combined action of high pressure (1 up to 4000 bar) and low temperature (‐22°C up to 0°C) was investigated. The effect of a high pressure/low temperature (HP/LT) treatment on the selected enzymes was compared to the effect of a freezing process at atmospheric pressure. It was found that (i) no irreversible inactivation of POD, PPO and BSA occurred after the HP/LT treatments tested, (ii) PME was only slightly irreversibly inactivated in the selected pressure and temperature domain (92% up to 80% of activity retention) and (iii) LOX was irreversibly inactivated to a large extent (3 up to 55% of activity retention) after the selected HP/LT treatments whereas a classical freezing at ‐18°C and atmospheric pressure caused only a 10% decrease in LOX activity. It could be observed that the enzymic activity after the treatment of both PME and LOX slightly decreased during storage in an ice bath.