Drying Characteristics, Color, and Functional and Chemical Properties of Figl (Raphanus sativus L.) Leaves and Petioles Under Convective Drying Conditions

Investigating the effect of drying temperature on the quality of the leaf and petiole parts of Figl is essential to use the leaf and petiole for food formulation or as food ingredients in developing countries to overcome the problem of food security. In this study, the effect of drying temperature (27.20^°C ± 2.1^°Cor in the sun, 40°C, 50°C, and 60°C) on drying rate, moisture diffusivity, color, and functional and chemical properties of the leaf and petiole was investigated. A two-way analysis of variance was performed using a Statistical Analysis System to evaluate the effect of drying temperature on the drying characteristics, color, and chemical and functional properties of the leaves and petioles of Figl. The effective diffusivity values changed from 4 × 10⁻¹² to 8.2 × 10⁻¹² m²/s and 2.1 × 10⁻⁰⁸ to 4.9 × 10⁻⁸ m²/s for the leaf and petiole of Figl, respectively, within the given temperature range. The bulk densities of the leaf and petiole of Figl were in the range of 0.20–0.35 g/mL and 0.27–0.41 g/mL, respectively. The results indicated that drying rate, moisture diffusivity, water activity, ascorbic acids, and delta decreased with drying temperature, whereas the functional properties of both the leaf and petiole increased with drying temperature. Comparatively, the petiole part showed better results in terms of functional and chemical properties than the leaf at all drying temperatures. From the results of the study, in terms of functional and chemical properties, drying of the petiole at 50°C for 120 min was found to be the optimum temperature for better quality.