Evaluation of the effect of slice thickness and drying temperature on selected characteristics of orange-fleshed sweet potatoes (Ipomoea batatas L.)

Abstract

Orange-Fleshed Sweet Potato (OFSP) is rich in beta-carotene, a precursor of vitamin A that combats Vitamin A Deficiency (VAD). Due to its high moisture content, drying is essential to extend shelf life, though high temperatures can degrade nutrients. This study examined the effects of slice thickness (2, 4, 6 mm) and drying temperatures (50, 60, 70? °C) on drying kinetics and quality of OFSP. Drying parameters such as Effective Moisture Diffusivity (D_eff) and Activation Energy (E_a) were determined. Beta-carotene content and total colour change (?E) were evaluated. Drying data were fitted to six thin-layer models. Logarithmic model provided the best fit (R² = 0.999, ?² = 0.000 at 6 mm, 60? °C). D_eff values ranged from 2.286×10?? to 3.195×10?? m²/s, and E_a ranged from 31.50 to 39.10 kJ/mol. The highest beta-carotene (29.12 mg/100 g) was retained at 6 mm, 50?°C, while the best colour (?E = 62.02) was at 4 mm, 60?°C. Overall, 4 mm slices offered a balance between drying efficiency and quality retention. Findings support optimized drying of OFSP to improve storage, nutrition, and food security, contributing to sustainable Development Goals (SDG) 1, 2, and 3.