Analysis of Heat and Mass Transfer in Freeze Drying

Jafar, Farial A; Farid, Mohammed

doi:10.1081/drt-120017746

Cited by 35 publications

(17 citation statements)

References 12 publications

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“…The higher values of R 2 and the lower values of P, RMSE and  2 will give the goodness of the fit. These parameters are calculated by equations (3) - (6), and are shown in Table 2. where MR expi are the experimental values of moisture ratios, MR prei are the predicted moisture ratios, N are the number of observations, and n is the number of constants.…”

Section: Figure 1 Drying Curvesmentioning

confidence: 99%

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Freeze-Drying Kinetics Approach of Soluble Coffee. Mass Transfer Parameters Estimation

Ghirişan¹,

Drăgan²,

Miclăuş³

2017

Studia UBB Chemia

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ABSTRACT. The present paper presents the freeze-drying kinetics of soluble coffee in order to determine the mass transfer parameters. Several semi-theoretical and empirical models were used to find the best fit to the experimental data. The applied models were compared using the coefficient of determination (R 2 ), the mean relative percent error (P), the root mean square error (RMSE) and the reduced chi-square ( 2 ). The Midilli model was found to fit better to the experimental freeze-drying data comparative to other models. The Fick's second law was employed to determine the effective diffusion coefficient (Deff).

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Section: Figure 1 Drying Curvesmentioning

confidence: 99%

“…The vaporized solvent (water) is transported through the porous layer of dried material. In contrast with mass transfer, which always flows through the dry layer, heat transfer can take place by conduction through the dry layer or through the frozen layer [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Freeze-Drying Kinetics Approach of Soluble Coffee. Mass Transfer Parameters Estimation

Ghirişan¹,

Drăgan²,

Miclăuş³

2017

Studia UBB Chemia

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“…동결건조는 영하의 온도에서 승화 를 통해 건조가 진행되기 때문에 성분의 변성 면에서 가 장 선호되는 방법이다 22) . 건조 전 특성을 잘 보존하며 건 조물의 재수화율이 높은 반면 23) , 공정에서 에너지 소모가 높으며 시간이 오래 걸리는 단점을 가지고 있다 24,25) .…”

Section: 산화질소(No)의 측정unclassified

Comparison of Index Compound Content and Anti-inflammatory Activity of Eucommiae Cortex by Various Drying Methods

Do¹,

Lee²,

Ha³

et al. 2017

J Korean Med Rehabil

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Objectives Eucommiae cortex is one of the frequently used herbs for musculoskeletal disorders, with well-known anti-inflammatory effect. Meanwhile, powdered form of herbal drugs is more advantageous than decoction form, in that storing and taking is more convenient. Thus, the authors aimed to investigate whether the drying method affects the index compound level and anti-inflammatory effect of eucommiae cortex water extract. Methods Eucommiae cortex was extracted in distilled water at 100 o C for 3 hours, filtered, and then evaporated under vacuum. One half of the sample was freeze-dried at −80 o C. Another half of the sample was added with dextrin and then spray-dried at 180 o C. To assess the possible change in index compound content, pinoresinol diglucoside was selected as the index marker. The content level of the index compound in various extract sample was quantified through high performance liquid chromatography. In addition, iNOS assay in LPS-induced RAW 264.7 cells was adopted to determine the anti-inflammatory effect of various extract samples. Furthermore, MTT assay was performed to confirm that the result of iNOS assay was not due to cytotoxicity. Results There was no significance difference in index compound content between extract samples obtained through two different drying methods. Anti-inflammatory activity of extract samples were similar at the matching concentration, regardless of the drying methods. Extract samples did not show any significant cytotoxicity.Conclusions Extract samples of eucommiae cortex were obtained through freeze-drying and spray-drying. Neither change in index compound content nor difference in anti-inflammatory activity was observed between drying methods. (J Korean Med Rehabil 2017;27(1):19-25)

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“…Freeze-drying is a special technology of dehydrating frozen materials by sublimation under high vacuum [9,6]. One of its possible applications comes from the food industry, where it can be used for drying certain kinds of food-stuffs, for example carrots or coffee.…”

Section: Introductionmentioning

confidence: 99%

On adaptive time stepping for large-scale parabolic problems: Computer simulation of heat and mass transfer in vacuum freeze-drying

Georgiev¹,

Kosturski²,

Margenov³

et al. 2009

Journal of Computational and Applied Mathematics

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a r t i c l e i n f o MSC: 65M60 Keywords: Vacuum freeze drying Zeolites Heat and mass transfer Parabolic PDE Finite element method MIC(0) preconditioning a b s t r a c tThe work is motivated by the problem of freeze-drying, which is a process of dehydrating frozen materials by sublimation under high vacuum. In particular, it concerns the mathematical modelling and computer simulation of the heat and mass transfer with the core in solving the time-dependent nonlinear partial differential equation of parabolic type.Instead of a uniform discretization of the considered time interval, an adaptive time-stepping procedure is applied in an effort to optimize the whole simulation. The procedure is based on the local comparison of the Crank-Nicolson and backward Euler approximations. The results of numerical experiments performed on a selected real-life problem are included.

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Analysis of Heat and Mass Transfer in Freeze Drying

Cited by 35 publications

References 12 publications

Freeze-Drying Kinetics Approach of Soluble Coffee. Mass Transfer Parameters Estimation

Freeze-Drying Kinetics Approach of Soluble Coffee. Mass Transfer Parameters Estimation

Comparison of Index Compound Content and Anti-inflammatory Activity of Eucommiae Cortex by Various Drying Methods

On adaptive time stepping for large-scale parabolic problems: Computer simulation of heat and mass transfer in vacuum freeze-drying

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