Effect of thermal treatment on steam peeled potatoes

Abstract Within this work, the effect of the heating treatment during the steam peeling of potatoes was assessed. The minimal temperature and cooking values necessary for peeling to take place, and the consequences produced at cellular level, especially in pectic constituents, were determined. Penetrations of the peeling front and the final potato radial coordinate after steam peeling of spherical shaped potatoes were experimentally determined in a specially designed steam peeler. Heat transfer coefficient of the steam peeler and thermal diffusivity of the potato tissue were experimentally obtained. Minimum peeling temperature and cooking value were theoretically estimated. Transmission and scanning electronic microscopy (TEM and SEM) studies were also performed in fresh and steam peeled potatoes. Results showed that for steam peeling to take place it is necessary that the thermal treatment satisfies the following conditions: that the cooking value reaches at least 17 s at 100°C, and that the temperature reaches at least 100°C.