The effect of structural changes on the activity of peroxidase with different initial state under high-pressure freezing

The combined impact of initial state, pressure, and freezing on peroxidase denaturation during high-pressure freezing (HPF) processing of enzyme-containing foods remains unclear. This study investigated solid-liquid (initial low/high concentration) biphasic peroxidase using spectroscopic and computer simulation techniques to analyze structural changes affecting peroxidase (POD) activity under HPF. The results indicate that the primary factors determining POD activity during HPF treatment can be ranked as follows: concentration > physical state > pressure > freezing. Higher initial concentrations strengthen protein interactions, leading to a 1% increase in the molecular diameter and a 34% increase in molecular height of HL-POD, thereby increasing aggregation likelihood during crystallization and facilitating structural changes that activate enzymes by 6–17%. The amide I peak proves to be a reliable indicator for monitoring both POD activity and structural alterations. This study offers valuable insights for optimizing HPF technology in food processing. [Display omitted] •Impact ranking on activity as follows: concentration > physical state > pressure > freezing.•Higher concentrations led to enhanced protein molecule interaction.•Enhancement of α-helix structure and hydrogen bonding leads to increased activity.