ICAR Research Data Repository for Knowledge Management
Development of a desiccant based food drying system
KrishiKosh
View Archive Info| Field | Value | |
| Title |
Development of a desiccant based food drying system
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| Creator |
Attkan, Arun Kumar
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| Contributor |
Yadav, Y.K.
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| Subject |
Desiccant dehumidifier, Regeneration temperature, Air mass flow rate, Absolute humidity, Fenugreek leaves, Moisture content
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| Description |
The performance of desiccant dehumidifier at different air flow rates, regeneration temperatures and at different inlet conditions has been carried out and the variation in absolute humidity, adsorption and desorption capacity was studied. It observed that when air entering the dehumidifier is more humid, it will be more humid leaving the dehumidifier. Process air outlet temperature is higher than the inlet air temperature due to the heat of sorption of moisture removed from the air is converted to sensible heat. The effect of regeneration temperature on process outlet absolute humidity has also been studied and it was observed that as regeneration temperature increases, the process out absolute humidity increases and similar effect has been observed with increase in air mass flow rate. Experimental tests were conducted to evaluate the performance of dehumidifier for air mass flow rate of 0.32 to 1.30 kg/s and regeneration temperature between 60 to 120°C and it was established that the regeneration temperature in the range of 90 to 120°C and air mass flow rate of 0.95 to 1.30 kg/s gave optimum performance. A desiccant based food drying system was developed and its performance was evaluated for drying of fenugreek leaves (methi) at drying air temperatures of 45, 50 and 55°C and results compared with tray drying. The parameter observed included moisture content, rehydration ratio, ascorbic acid, total carotenoids, moisture diffusivity and sensory evaluation. Results indicated that at higher temperature, drying rate was faster in desiccant dehumidifier dryer as compared to tray dryer. The moisture content of fenugreek leaves was reduced from 88.6 % (wb) to 5 % (wb) in 11, 10 and 8 hours in desiccant dryer as compared to 13, 11 and 9 hours in tray dryer at drying air temperature of 45, 50 and 55°C, respectively. The effective diffusivity values for desiccant drying and tray drying was varied in range of 4.06E-08 to 5.71E-08 m²/s and 3.40E-08 to 5.08E-08 m²/s, respectively. The fresh fenugreek leaves contained 209.2 mg/100 g ascorbic acid and 32.4 mg/100g of total carotenoids. The ascorbic acid retention among the dehydrated samples was maximum192.4, 185.3 and 170.6 mg/100g in desiccant dried fenugreek leaves and 170.5, 135.7 and 122.4 mg/100g in tray dried sample at drying air temperature of 45, 50 and 55°C, respectively. The fenugreek leaves dried at 45°C in desiccant dryer had superior green color and maximum retention of nutrients and hence the desiccant dryer is a promising alternative for food drying. |
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| Date |
2016-09-09T13:50:49Z
2016-09-09T13:50:49Z 2013 |
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| Type |
Thesis
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| Identifier |
http://krishikosh.egranth.ac.in/handle/1/76205
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| Language |
en
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| Format |
application/pdf
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| Publisher |
CCSHAU
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