Heat and Moisture Transfer Model for Onion Drying

Kalbasi, Mansour

doi:10.1081/drt-120024492

Cited by 11 publications

(8 citation statements)

References 17 publications

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“…Therefore, the drying rate is limited by a moisture diffusion process and can be described by the Fick's second law of unsteady state diffusion given in Eq. (6). The solution of Fick's second law in slab geometry, with the assumptions of moisture migration being by diffusion, negligible shrinkage, constant diffusivity was follows as in Eq.…”

Section: Development Of Mathematical Modelsmentioning

confidence: 99%

“…Dehydration operations are important steps in food processing industry, which involves a process of moisture removal due to simultaneous heat and mass transfer. Drying provides a longer shelf-life to the food, cheaper transportation cost, and smaller space demand during storage (6,7). Dehydrated onion has become a standard food ingredient in a wide range of food products (8) such as ketchup, soups, salad dressings, sausage and meat products, potato chips, crackers, and many other convenience foods (9).…”

Section: Introductionmentioning

confidence: 99%

“…Simulation models are needed for design development and for optimal operation of the drying systems. Although several studies have reported in the literature on the drying behavior of onion (2,4,6,7,(10)(11)(12), no sufficient information is available on the drying kinetics of onion slices during conventional air-drying which is the most frequently used dehydration operation in food and chemical industries.…”

Section: Introductionmentioning

confidence: 99%

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Drying Kinetics of Onion Slices in a Hot-air Dryer

Lee

Kim²

2008

JFN

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Onion slices were dehydrated in a single layer at drying air temperatures ranging from 50～70 o C in a laboratory scale convective hot-air dryer at an air velocity of 0.66 m/s. The effect of drying air temperature on the drying kinetic characteristics were determined. It was found that onion slices would dry within 210～460 min under these drying conditions. Moisture transfer during dehydration was described by applying the Fick's diffusion model and the effective diffusivity changed between 1.345 × 10-8 and 2.658 × 10-8 m 2 /s. A non-linear regression procedure was used to fit 9 thin layer drying models available in the literature to the experimental drying curves. The Logarithmic model provided a better fit to the experimental drying data as compared to other models. Temperature dependency of the effective diffusivity during the hot-air drying process obeyed the Arrhenius relationship with estimated activation energy being 31.36 kJ/mol. The effect of the drying air temperature on the drying model constants and coefficients were also determined.

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Section: Development Of Mathematical Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Drying Kinetics of Onion Slices in a Hot-air Dryer

Lee

Kim²

2008

JFN

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“…Similar results were reported by Lewicki, Rajchert, and Nowark (1998). Kalbasi (2003) also reported that drying rate at high moisture content was a stronger function of air temperature. This might be due to higher vapour pressure difference as the driving force for moisture removal owing to higher moisture content of the product and higher drying air temperature.…”

Section: Drying Characteristics Of Onion Slicesmentioning

confidence: 96%

Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.)

et al. 2012

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A prototype heat pump dryer has been developed for drying of fruits and vegetables at low temperature and relative humidity to maintain the quality of dried product. Onions, of Nasik red variety were peeled, trimmed and sliced to 2 mm thickness. The onion slices were dried in the heat pump dryer at 35• C (32 % R.H.), 40• C (19 % R.H.) and 50• C (15 % R.H.). Samples were also dried in a hot air dryer at 50• C (52 % R.H.) for comparison. The drying rate increased with increase in drying air temperature, associated with reduced R.H., in the heat pump dryer. Drying took place mainly under the falling rate period. The Page equation, resulting in a higher coefficient of determination and lower root mean square error, better described the thin-layer drying of onion slices than the Henderson and Pabis equation. Heat pump drying took less drying time of 360 min and yielded better quality dried product, with higher retention of ascorbic acid and pyruvic acid and lower colour change, as compared to a hot air dryer at the same drying air temperature of 50• C.

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“…Drying can extend the storage life of a substance and is effective for reducing storage volume to lower delivery cost [6][7].…”

Section: Introductionmentioning

confidence: 99%

Analysis on the Heat Efficiency of Hot-Air Drying System

Ha¹,

Kim²,

Wang³

2015

Proceedings of the 2015 International Conference on Environmental Engineering and Remote Sensing

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Abstract-Conveyor-belt hot-air drying equipment was developed and used in this study to investigate the feasibility of new heatefficiency-improvement technology. This novel technology reduces the amount of heat generated by the heater in the new hot-air drying furnace. Sludge sample types A and B used in the study were obtained from a city water treatment plant. Samples that had undergone first-stage dehydration were collected frequently during the experimental period. The result from analyzing the total moisture content in the sludge showed that the average total moisture content detected in Type A sludge samples was 35.12% and that in Type B samples was 51.3%. These samples were treated using various temperatures and hot-air supply rates. Evaluation of the drying efficiency of the conveyorbelt hot-air drying system using the Freeman-Carroll method, showed that the drying rate remained constant with temperature and power. Although Type B samples were dried at high temperature, their drying rates were similar to those of Type A samples, which could be dried at lower temperature. This was because of the drying effectiveness of the hot-air as well as the steady temperature inside the dryer equipment.

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Heat and Moisture Transfer Model for Onion Drying

Cited by 11 publications

References 17 publications

Drying Kinetics of Onion Slices in a Hot-air Dryer

Drying Kinetics of Onion Slices in a Hot-air Dryer

Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.)

Analysis on the Heat Efficiency of Hot-Air Drying System

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