In the paper, the effect was determined of thermal treatment, run in a convection-steam oven at different heating parameters, on changes in some textural properties of the Aura F1 variety of pumpkin. The samples of pumpkin pulp were heated in a convection-steam oven at temperatures of 80 and 100 °C, with different steam amounts added (0 to 100 %), during 5, 10, 15, 20, and 25 minute periods. Next, the samples underwent strength tests and hardness, elasticity, and chewiness were measured. It was found that the heating in the convection-steam oven caused the textural properties of pumpkin pulp, i.e. hardness, elasticity, and chewiness to change. The extent and the profile of those changes depended on the process parameters applied under the research program, i.e. the temperature and heating time, and the amount of the steam added. Already 5 minutes after the thermal treatment began a decrease in the analysed parameter values of the pumpkin pulp was reported. On the basis of the classification and regression trees it was found that the steam added had the greatest effect on the changes in the pulp hardness, whereas the time and temperature of heating affected those changes to a lesser extent. The addition of even the smallest amount of steam (20 %) caused the hardness of the pumpkin pulp to essentially decrease. A further increase in the amount of the added steam did not cause such a radical reduction in the hardness. Similar correlations were found in the case of the chewiness of the pumpkin pulp; a 20% addition of the steam caused the chewiness to decrease irrespective of the temperature and time of heating. A further increase in the amount of steam added did not cause statistically significant changes in this parameter. While measuring the elasticity, no clear-cut effect of the heating parameters was reported. Similar to the hardness and chewiness, the amount of the steam added had the greatest impact on the changes in the elasticity; however, the course of those changes was inconsistent.
pumpkin, heat treatment, convection-steam oven