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Characterization of Osmotic Dehydration and Subsequent Hot-Air Drying of Chili Pepper

YIN Xiaofeng, YANG Mingjin, ZHANG Yinhang, GAO Bo, XIE Shouyong, YANG Ling*   

  1. Chongqing Key Laboratory of Agricultural Equipment for Hilly and Mountainous Regions, College of Engineering and Technology, Southwest University, Chongqing 400715, China
  • Online:2017-01-15 Published:2017-01-16

Abstract: Osmotic dehydration, hot-air drying and rehydration experiments were sequentially carried out to investigate
the osmotic dehydration, hot-air drying and rehydration characteristics of chili pepper as well as final product quality by
measuring water loss, solid gain, ratio between water loss and solid gain, effective moisture diffusion coefficient, activation
energy, VC retention rate, pungency degree, rehydration rate, recovery rate, and sensory evaluation. The results showed
that with the increase in temperature or salt concentration of the osmotic solution, water loss and solid gain of chili pepper
increased. Hot-air temperature was the main factor that affects the hot-air drying, followed by air velocity. With the increase
in hot-air temperature, the effective moisture diffusion coefficient of chili pepper samples increased and the activation
energy of direct hot-air drying and hot-air drying after osmotic dehydration were (53.25 ± 1.08) and (44.42 ± 0.88) kJ/mol,
respectively at an air velocity of 1.8 m/s. The effective moisture diffusion coefficient, VC retention rate, pungency degree,
rehydration rate and recovery rate of dehydrated and hot-air dried chili pepper processed by osmotic ion followed by hotair
drying were higher than those of the hot-air dried sample, and the rehydration characteristics and quality of the former
sample were better than those of the latter one.

Key words: osmotic dehydration, hot-air drying, rehydration, quality, chili pepper

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