Convective drying of organic pear pulp in a thin stagnant layer

Abstract

The aim of this paper is to present the influence of convective drying of organic pear pulp and adding ascorbic acid on changes in color, the difference in vitamin C content and also show the kinetics of convective drying. It was a two-factor experiment. The first factor was the air temperature needed for drying, between 45 °C and 65 °C, with a constant speed of drying air of 1.5 m/s; the second factor of the experiment was the adding of ascorbic acid to the pear pulp in the amount of 1 % and 2 % of the full mass of the prepared pulp. The lowest change in color was achieved by adding ascorbic acid in the amount of 2 % of the full mass of the pulp and drying air temperature of 45°C (ΔE= 23.981). The highest change was accomplished at the air temperature of 65 °C and by adding ascorbic acid in the amount of 1% (ΔE= 30.039). With samples where ascorbic acid was added reduction of vitamin C was over 99 % with all samples. By examining the kinetics of convective drying based on statistical indicators R, X2, RMSE, models Page and Logarithmic are the best in representing convective drying of pear pulp at air temperatures of od 65 °C and 45 °C respectively.

Keywords

• organic pear
• convective drying kinetic
• mathematical modeling
• vitamin c
• color change
• fruit leather-rolls