Journal of Agricultural Machinery
with the collaboration of Iranian Society of Mechanical Engineers (ISME)

Vacuum-infrared Drying of Okra Slices: Kinetics, Quality Analysis, and Optimisation

Articles in Press

Document Type : Research Article- En

Authors

F. SalehNezhad
Y. Mansoori
S. M. Safieddin Ardebili

Department of Biosystems Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

https://doi.org/10.22067/jam.2025.96137.1442
Abstract
Okra (Abelmoschus esculentus L.) slices were dried using vacuum-infrared drying method. A laboratory-scale dryer was designed and fabricated to control the drying parameters and monitor the weight change of samples. The parameters examined included temperature (50, 55, 65, 75, and 80ºC) and absolute pressure (5, 21, 53, 85, and 101 kPa). The response factors were drying time, drying rate, effective diffusivity, specific energy consumption, colour change (ΔE and a/a0), and rehydration ratio. The results from the response surface methodology indicated that the optimal conditions for minimising drying time and maximising green colour preservation were a pressure of 5 kPa and a temperature of 51ºC. Under these conditions, the corresponding responses of dried okra slices were 173 min for drying time, 0.24 %wb min-1 for drying rate, 1.44×10-9 m2 s-1 for effective diffusivity, 32.6 kWh kg-1 for specific energy consumption, 12.64 for colour change, 0.75 for relative greenness, and 6.8 for rehydration ratio. Additionally, the findings demonstrated that the combination of pressures lower than 20 kPa with infrared drying effectively enhanced the performance factors of the dryer while preserving the colour of dried okra slices.

Keywords

Okra
Optimisation
Vacuum-infrared drying
Subjects

Authors retain the copyright. This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0)

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Journal of Agricultural Machinery

Articles in Press, Accepted Manuscript
Available Online from 06 January 2026

  • Receive Date 26 October 2025
  • Revise Date 24 November 2025
  • Accept Date 21 December 2025
  • First Publish Date 06 January 2026

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