Drying Kinetics and Activation Energy of Asparagus Root (Asparagus racemosus Wild.) for Different Methods of Drying

Deepika Kohli^1*, Navin Chand Shahi¹, Ajit Kumar²

¹Department of Post-Harvest Process and Food Engineering, G. B. Pant University of Agriculture and Technology, Pantnagar, India, 263145
²Department of Horticulture, G. B. Pant University of Agriculture and Technology, Pantnagar, India, 263145.

Corresponding Author Email: deepikaprp27@gmail.com

Drying reduces the water activity of food product and hence increases the shelf life of the food. In the present study, fresh asparagus roots were pretreated in hot water at 80oC for 5 min. The methods of drying used for the study were tray drying, solar drying, vacuum drying and fluidized bed drying at four temperature levels 40, 50, 60 and 70oC. The complete drying of asparagus follow falling rate period only. The total time for drying decreases with increase in temperature of drying air from 40oC – 70oC. Fluidized bed dryer has a highest average drying rate as compare to tray dryer, solar dryer and vacuum dryer. Four empirical models, namely Page’s, Exponential, Generalized exponential and Logarithmic model were fitted in the drying data to describe the phenomena of drying process using a linearized regression technique. It was found that the Page’s model was best as it describe most precisely about the drying behavior of asparagus roots. The effective moisture diffusivity of asparagus roots varies from 7.14 × 10-9 to 3.70 × 10-8 m2/s and it was also found that diffusivity increases with increase in temperature. The activation energy was found to be from 11.797 to 30.318 kJ/mol.

Asparagus roots; Activation energy; Drying; Diffusivity; Empirical models

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