Combined effect of high pressure, temperature and holding time on polyphenoloxidase and peroxidase activity in banana (Musa acuminata)

Polyphenoloxidase and peroxidase enzyme activities were evaluated following combined pressure, temperature and holding time treatment in banana (Musa acuminata). Using pressures of up to 110 MPa, temperatures of up to 70°C and holding times of up to 25min, based on a 2³ central composite design, the interactive effects were found to significantly influence the activity of both enzymes in prepared banana pulp. Temperature and pressure were found to influence the inactivation of polyphenoloxidase separately, while temperature, pressure and holding time were found to influence the loss of peroxidase in the banana, although no significant interactive effects were found. The reduction in polyphenoloxidase activity was found to be less influenced by the combined treatment than peroxidase activity, thought to be due to solubilisation of the enzyme and effects of the soluble solids content.