Effect of thermal treatment on steam peeled potatoes

Within this work, the effect of the heating treatment during the steam peel ing of potatoes was assessed. The minimal temperature and cooking values ne cessary for peeling to take place, and the consequences produced at cellula r level, especially in pectic constituents, were determined. Penetrations o f the peeling front and the final potato radial coordinate after steam peel ing of spherical shaped potatoes were experimentally determined in a specia lly designed steam peeler. Heat transfer coefficient of the steam peeler an d thermal diffusivity of the potato tissue were experimentally obtained. Mi nimum peeling temperature and cooking value were theoretically estimated. T ransmission and scanning electronic microscopy (TEM and SEM) studies were a lso performed in fresh and steam peeled potatoes. Results showed that for s team peeling to take place it is necessary that the thermal treatment satis fies the following conditions: that the cooking value reaches at least 17 s at 100 degrees C, and that the temperature reaches at least 100 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved.