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چکیده
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In this study, three different apparatuses of near infrared-vacuum (40 to 60 °C and 20 to 60 kPa), multi-stage semi-industrial continues dryers (40–60 °C) and open sun condition were implemented in lavender leaves drying. Effective moisture diffusivity, antioxidant capacity, total phenol content and color index were determined in all of the experiments. Effective moisture diffusivity variations of lavender leaves in near infrared-vacuum dryer were significant. Effective moisture diffusivity variations for lavender leaves drying in multi-stage semi-industrial continuous, were significant only for changes of air temperature of first stage and the highest value of effective moisture diffusivity in multi-stage semi-industrial continuous dryer was achieved at air temperature order of 60, 40 and 60 °C for first, second and third drying stages, respectively. Changes of antioxidant capacity and total phenolic content in near infrared-vacuumdryer were insignificant, but the effect of air temperature on changes of antioxidant capacity and total phenol content under multi-stage semi-industrial continuous drying was significant. Green color change was significant for both of near infrared-vacuum and multi-stage semi-industrial continues dryers and product color changed to yellow. In open sun condition, total phenol content and antioxidant declined, strongly, and color of lavender leaves changed to yellow-red. With respect to the quality indices, the near infrared-vacuum dryer can be considered as the best apparatus for lavender leaves processing.
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