Changes in the polyphenolic profile and oxidoreductases activity under static and multi-pulsed high pressure processing of cloudy apple juice

The purpose of the study was to assess the effect of static and multi-pulsed high pressure processing (HPP) (300-600 MPa, 5-15 min) on the changes in the polyphenolic profile, polyphenoloxidase (PPO) and peroxidise (POD) activities and colour of apple juice. Content of (-)-epicatechin, procyanidin B2, phloretin isomers and phloridzin was detected using Triple-TOF-LC-MS/MS analysis. After HPP treatment, 1,2-disinapoyl-2-feruloylgentiobiose was detected, whereas sinapoyl glucose was degraded after applying 450 MPa and 600 MPa in single pulse, therefore indicating sensitivity of this compound to high pressure and/or polymerization caused by enzymatic reactions. The highest inactivation of PPO (95%) and POD (26%) was observed at 600 MPa. The multi-pulsed HPP (300 MPa x 3 pulses) resulted in higher reduction in oxidoreductive enzyme activity than higher pressure in single pulse (450 MPa). Statistical changes in the colour parameters were observed in pressurized samples, with the lowest delta E values for 300 MPa x 3 pulses.

Automated summary

The study assessed the effects of static and multi-pulsed high pressure processing on the polyphenolic profile, enzyme activities, and color of apple juice. The results showed that high pressure treatment caused changes in the polyphenolic compounds and enzymes, and multi-pulsed high pressure treatment had a larger impact on the enzyme activity. Additionally, pressure treatment led to changes in the color parameters.