Effects of hot‐water and steam blanching of sliced potato on polyphenol oxidase activity

Summary

The worldwide potato production is considered the fourth-most important food sector due to the increasing use of potatoes as raw materials for high-convenience food. Colour is a crucial quality attribute in fresh-cut potatoes, and enzymatic browning, due to polyphenols oxidase (PPO), is related to unacceptability by consumer. Among additives used to minimize discoloration, sulphites are very common, but affected by health-related hazards and marketing issues. Viable alternatives are thermal treatments, used to inactivate enzymes and improve product shelf-life. In this study, the efficacy of hot-water and steam blanching from 80 to 90°C, used to inactivate PPO in 1-cm potato slices, was evaluated in terms of inactivation kinetic, substrate specificity and transition state parameters. In general, all treatments inactivated PPO and reduced its kinetic efficiency. In detail, results from thermal inactivation kinetic promoted hot-water blanching at 90°C for approx. 2 min as the fastest treatment to obtain colour-stable potato slices.