Mathematical modeling of the primary and secondary vacuum freeze drying of random solids at microwave heating

Nastaj, J.; Witkiewicz, K.

doi:10.1016/j.ijheatmasstransfer.2009.06.015

Cited by 46 publications

(11 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…, 2003). MFD is a multi‐stage operation which contains the primary drying stage and secondary drying stage (Nastaj & Witkiewicz, 2009). In the primary drying stage, ice greatly influences the ɛ′′ while in the secondary drying stage the starch content of the sample is the main factor determining the dielectric loss factor.…”

Section: Resultsmentioning

confidence: 99%

Comparison of the effect of microwave freeze drying and microwave vacuum drying upon the process and quality characteristics of potato/banana re‐structured chips

Jiang

Zhang

Mujumdar

et al. 2011

Int J of Food Sci Tech

View full text Add to dashboard Cite

This study investigated the drying characteristics of microwave freeze-drying (MFD) ⁄ microwave vacuum drying (MVD) of banana ⁄ potato restructured chips of varying proportion and microwave power. The results showed the MFD drying time had a maximum one-hour time difference between the samples treated with 2 W g )1 and 3 W g )1 microwave power; and the higher potato content samples have about 30 min predominance than low potato content samples in drying time and the total drying time of MVD samples was less than 60 min. For the rehydration ratio, MFD samples were far superior to the MVD samples. The MFD samples had more than 4.5 rehydration ratio. The data of the colour difference metre showed that 3 W g )1 microwave power would make samples slightly charred. The biggest differences between the MFD and MVD chips lie in their texture and shape; the hardness of MVD samples was 30.86 N, thrice higher than MFD samples.

show abstract

Section: Resultsmentioning

confidence: 99%

Comparison of the effect of microwave freeze drying and microwave vacuum drying upon the process and quality characteristics of potato/banana re‐structured chips

Jiang

Zhang

Mujumdar

et al. 2011

Int J of Food Sci Tech

View full text Add to dashboard Cite

show abstract

“…This drying process is conventionally divided into three stages: pre-freezing of wet material, primary drying stage (sublimation of frozen solvent under vacuum), and secondary drying stage (desorption of residual bound water from material matrix) (Nastaj and Ambrożek, 2006;Nastaj and Witkiewicz, 2009). To improve storage stability of dried products, residual water after the primary drying stage may further be removed by desorption in the secondary drying stage (Nam and Song, 2007).…”

Section: Freeze Drying (Fd)mentioning

confidence: 99%

Recent developments in high-quality drying of vegetables, fruits, and aquatic products

Zhang

Chen

Mujumdar

et al. 2015

Critical Reviews in Food Science and Nutrition

267

View full text Add to dashboard Cite

Fresh foods like vegetables, fruits, and aquatic products have high water activity and they are highly heat-sensitive and easily degradable. Dehydration is one of the most common methods used to improve food shelf-life. However, drying methods used for food dehydration must not only be efficient and economic but also yield high-quality products based on flavor, nutrients, color, rehydration, uniformity, appearance, and texture. This paper reviews some new drying technologies developed for dehydration of vegetables, fruits, and aquatic products. These include: infrared drying, microwave drying, radio frequency drying, electrohydrodynamic drying, etc., as well as hybrid drying methods combining two or more different drying techniques. A comprehensive review of recent developments in high-quality drying of vegetables, fruits and aquatic products is presented and recommendations are made for future research.

show abstract

“…The coefficient of determination R 2 and Chi-square v 2 were used as statistical indicators for the analysis of the results. On the other hand, an Arrhenius type equation [21,26,35,36] was used to determine the diffusivity as function of the temperature:…”

Section: Numerical Procedures and General Considerationsmentioning

confidence: 99%

Modeling of water transport in roof tiles by removal of moisture at isothermal conditions

et al. 2011

View full text Add to dashboard Cite

The main objective of this article is to describe the drying process of ceramic roof tiles, shaped from red clay, using diffusion models. Samples of the product with initial moisture content of 0.24 (db) were placed inside an oven in the temperatures of 55.6, 69.7, 82.7 and 98.6°C; and the data of the drying kinetics were obtained. The analytical solutions of the diffusion equation for the parallelepiped with boundary conditions of the first and third kinds were used to describe the drying processes. The process parameters were determined using an optimization algorithm based on inverse method coupled to the analytical solutions. The analysis of the results makes it possible to affirm that the boundary condition of the third kind satisfactorily describes the drying processes. The values obtained for the convective mass transfer coefficient were between 8.25 9 10 -7 and 1.64 9 10 -6 m s -1 , and for the effective water diffusivity were between 9.21 9 10 -9 and 1.80 9 10 -8 m 2 s -1 . List of symbolsA n Coefficients of the analytical solution dependent on position (boundary condition of the third kind) B n Coefficients of the analytical solution for the average moisture content (boundary condition of the third kind) Bi Biot number (dimensionless) Bi 1 Biot number for the side of length L 1 (dimensionless) D Effective water diffusivity (m 2 s -1 ) h Convective mass transfer coefficient (m s -1 ) k, m, n Indexes of summations L 1 , L 2 , L 3 Dimensions of a parallelepiped (m) M Moisture content (kg kg -1 , dry basis) M(x, y, z, t) Moisture content at instant t in the position (x, y, z) (kg kg -1 , dry basis) M 0 Initial moisture content (kg kg -1 , dry basis) M eq Equilibrium moisture content (kg kg -1 , dry basis) MðtÞ Average moisture content at instant t (kg kg -1 , dry basis) M exp i Average moisture content of the ith experimental point (kg kg -1 , dry basis) M ana i Average moisture content determined by analytical solution (kg kg -1 , dry basis) R 2 Coefficient of determination (dimensionless) t Time (s) x, y, z Position in Cartesian coordinates (m)Greek symbols v 2 Chi-square or objective function l n Roots of the characteristic equation for boundary condition of the third kind r i Standard deviation of the ith experimental point

show abstract

Mathematical modeling of the primary and secondary vacuum freeze drying of random solids at microwave heating

Cited by 46 publications

References 40 publications

Comparison of the effect of microwave freeze drying and microwave vacuum drying upon the process and quality characteristics of potato/banana re‐structured chips

Comparison of the effect of microwave freeze drying and microwave vacuum drying upon the process and quality characteristics of potato/banana re‐structured chips

Recent developments in high-quality drying of vegetables, fruits, and aquatic products

Modeling of water transport in roof tiles by removal of moisture at isothermal conditions

Contact Info

Product

Resources

About