Journal of food science and technology(Iran)

Journal of food science and technology(Iran)

Optimization of red pepper drying conditions in a tray dryer with cross current air flow

Document Type : Original Article

Author
Zahra Hejri
Department of Chemical Engineering, Qu.C., Islamic Azad University, Quchan, Iran
10.48311/fsct.2026.118853.83028
Abstract
In this study, the effect of temperature, air velocity, and punching on the drying process of red pepper in a cross-flow tray dryer was investigated. Red pepper samples were dried at three temperatures of 55, 65, and 75 °C, two air velocities of 1 and m/s2, and with three preparation methods: unpunched, punched by a needle with a diameter of 2 mm (needle No. 1), and punched by a needle with a diameter of 3.5 mm (needle No. 2), and the quality indicators of the final product, including pungency, color, and moisture, were measured. According to the results of the experiments and statistical analyses, the optimal conditions for drying red pepper in a tray dryer with cross-flow air were temperature 65 ℃, punch diameter 2 mm, air velocity 2 m/s, and the drying rate under these conditions was 0.299 kgw/kgdm.h, pungency 0.427 mass percent of total capsicums, and the amount of extracted color based on optical absorption at a wavelength of 458 nm was 3.776. The results also showed that the Page and Midilli nonlinear models with very low RMSE and χ² values and high coefficient of determination provided a more accurate fit than the Newton model and therefore are more suitable for describing the drying kinetics of red pepper.
Keywords
Red pepper
tray dryer
temperature
punching
air velocity
Subjects
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Journal of food science and technology(Iran)
Volume 23, Issue 175 - Serial Number 175
September 2026
Pages 249-267