Combined high hydrostatic pressure and carbon dioxide inactivation of pectin methylesterase, polyphenol oxidase and peroxidase in feijoa puree

Abstract

A combined treatment of high hydrostatic pressure (HHP) and dense phase carbon dioxide (DPCD) was investigated to inactivate pectin methylesterase (PME), peroxidase (POD) and polyphenol oxidase (PPO) in feijoa (Acca sellowiana) puree. The treatments were HHP (HHP); carbonation and HHP (HHPcarb); carbonation+addition of 8.5mL CO2/g puree into the headspace of the package and HHP (HHPcarb+CO2). The different samples were treated at 300, 450 and 600MPa, for 5min.The residual POD and PPO activity decreased in the order HHP>HHPcarb>HHPcarb+CO2 at all pressures used. Treatments with HHP at 300MPa increased POD activity to 140%. The residual PME activity of HHPcarb and HHPcarb+CO2 samples at 600MPa (45–50%) was significantly (p<0.05) lower than for HHP treatment (65%).The simultaneous application of HHP and DPCD seems to synergistically enhance the inactivation of the enzymes studied, the CO2 concentration being a key process factor.