scholarly journals Freeze-Drying with Structured Sublimation Fronts—Visualization with Neutron Imaging

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1091 ◽  
Author(s):  
Nicole Vorhauer-Huget ◽  
David Mannes ◽  
Mathias Hilmer ◽  
Sebastian Gruber ◽  
Markus Strobl ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Measurement Techniques ◽  
Neutron Imaging ◽  
Pore Scale ◽  
Drying Process ◽  
Fractal Structures ◽  
Drying Time ◽  
Collapse Temperature ◽  
Sublimation Front ◽  
Prescriptive Analysis

The particular structure of the sublimation front in vacuum freeze-drying of porous media is, in most situations, not accessible at the pore scale. The classical measurement techniques access the process only globally. Knowledge about the structure of the front, however, is necessary for prescriptive analysis of freeze-drying, as it dictates not only drying velocity, drying time, and overall energy consumption, but also the material properties after drying. This is especially relevant in situations in which the freeze-drying process is carried out close to the collapse temperature of the product. We, therefore, study the sublimation of ice with neutron tomography and analyze the spatial formation of the dry space using the example of frozen cylindrical maltodextrin with drying parameters at the limit of material collapse. We show that the sublimation front forms unique fractal structures that differ strongly from the usual form of a flat front. Distinct dry fingers covering the sample, in addition to a fractal peripheral sublimation front, were observed. The findings are important for the understanding of freeze-drying processes and will serve as a basis for the development of microscale models of freeze-drying.

Development of a Compact Vacuum Freeze Drying for Jelly Fish (Schypomedusae)

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. Idrus Alhamid ◽  
M. Yulianto ◽  
Nasruddin M. ◽  
Engkos A. Kosasih
Keyword(s):  
Heat Loss ◽  
Freeze Drying ◽  
Moisture Ratio ◽  
Cold Trap ◽  
Chamber Pressure ◽  
Internal Cooling ◽  
Drying Process ◽  
Drying Time ◽  
Chamber Temperature ◽  
Drying Chamber

A new design of a vacuum freeze drying with internal cooling and heater from condenser’s heat loss was built and tested. The dryer was used to dry jelly fish (scyphomedusae) to study the effect of drying parameter such as temperature within the drying chamber on mass losses (evaporation) during freezing stage and moisture ratio at the end of drying process and also the drying rate of vacuum drying process. The cold trap temperature rise in when activated the heating from condenser’s heat loss. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve base on different drying chamber temperature. The result of this experiment show that mass loss during freezing stage decreased with a decrease in drying chamber temperature with constant pressure. Drying time reduced with an increase in drying temperature. Drying chamber temperature decreasing has a result pressure saturation of material lower than drying chamber pressure have an effect mass transfer should not occurs.

scholarly journals Effect of Freeze-Drying on Quality and Grinding Process of Food Produce: A Review

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 354 ◽  
Author(s):  
Timilehin Martins Oyinloye ◽  
Won Byong Yoon
Keyword(s):  
Glass Transition ◽  
Freeze Drying ◽  
Structural Changes ◽  
Morphological Changes ◽  
Energy Requirement ◽  
Quality Attributes ◽  
Processing Unit ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried

Freeze-drying is an important processing unit operation in food powder production. It offers dehydrated products with extended shelf life and high quality. Unfortunately, food quality attributes and grinding characteristics are affected significantly during the drying process due to the glass transition temperature (during drying operation) and stress generated (during grinding operation) in the food structure. However, it has been successfully applied to several biological materials ranging from animal products to plants products owning to its specific advantages. Recently, the market demands for freeze-dried and ground food products such as spices, vegetables, and fruits are on the increase. In this study, the effect of the freeze-drying process on quality attributes, such as structural changes, the influence of glass transition during grinding, together with the effect on grinding efficiency in terms of energy requirement, grinding yield, and morphological changes in the powder as a result of temperature, drying time were discussed. An overview of models for drying kinetics for freeze-dried food sample, and grinding characteristics developed to optimize the drying processes, and a prediction of the grinding characteristics are also provided. Some limitations of the drying process during grinding are also discussed together with innovative methods to improve the drying and grinding processes.

Parameter Optimization of Vacuum Freeze-Drying Processing on Tan Lamb

2014 ◽  
Vol 513-517 ◽  
pp. 4281-4284
Author(s):  
Chen Ji ◽  
Yan Li Fan ◽  
Gui Shan Liu ◽  
Wei Wang ◽  
Rui Ming Luo
Keyword(s):  
Freeze Drying ◽  
Orthogonal Design ◽  
Chamber Pressure ◽  
Drying Process ◽  
Quadratic Regression ◽  
Plate Temperature ◽  
Drying Time ◽  
Material Thickness ◽  
Heating Plate ◽  
Drying Chamber

In this paper, the effects of drying chamber pressure, heating plate temperature and material thickness on the drying time of Tan lamb in vacuum freeze-drying process were studied using quadratic regression orthogonal design. The results showed that the drying time was significantly affected by drying chamber pressure, heating plate temperature and material thickness as well as the interaction of heating plate temperature and material thickness. The optimized parameters were drying chamber pressure 27.9 Pa, heating plate temperature 47.9°C and material thickness 4.3 mm. On these parameters, the drying time was 4.3 h.

Manufacturing Research with Key Applied Technology in Vacuum Freeze-Drying Leisure Meat Processing

2014 ◽  
Vol 1056 ◽  
pp. 88-91
Author(s):  
Yan Ma ◽  
Shuai Wu ◽  
Xian Jun Meng ◽  
Wei Wei Liu
Keyword(s):  
Freeze Drying ◽  
Eutectic Point ◽  
Meat Processing ◽  
Drying Process ◽  
System Pressure ◽  
Limited Temperature ◽  
Freeze Dried ◽  
Applied Technology ◽  
Collapse Temperature ◽  
Western Germany

This paper studies thefreeze-drying process of Chinese style ham and western Germany fruit tree tenderloin , get their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics, and determine the precool temperature and highest limited temperature of sublimation interface . The effects of system pressure on freeze-dried rate in freeze-drying process is discussed, determining the methods of regulating pressure circularly.

scholarly journals ASSESSMENT OF FREEZING PRE-TREATMENTS FOR THE FREEZE DRIED OF APPLE SLICES

2013 ◽  
Vol 17 (2) ◽  
pp. 3-14 ◽  
Author(s):  
Tamás Antal ◽  
László Sikolya ◽  
Benedek Kerekes
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Color Difference ◽  
Freezing Rate ◽  
Slow Freezing ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried ◽  
Apple Slices

Abstract The effect of freezing rate on the quality of dried Jonagold and Idared was studied. Apple slices underwent various pre-treatments, i.e. freezing in household freezer (freezing rate: 0,5 °C/min), contact plate freezing (2 °C/min) and vacuum-freezing (3 °C/min). The quality of the freeze dried product was then evaluated in terms of water activity, hardness, color and rehydration. The freezing in household freezer (slow freezing rate) significantly reduces the duration of the freeze drying process and consequently the process costs. The slow freezing rate allows the growth of large ice crystals at the beginning of the freeze-drying process, this fact should consequently lead to larger pores and injured cell walls and thus to shorter freeze drying time. Quality of the freezing in household freezer product was assessed as higher than the quality of the other freezing pre-treated material. Slow freezing rate resulted softer texture and higher rehydration capacity, than that of other pre-treated samples. In all cases, slow freezing lead to lower final moisture content, total color difference and water activity.

scholarly journals Pulsed electric field enhanced freeze-drying of apple tissue

2019 ◽  
Vol 37 (No. 6) ◽  
pp. 432-438 ◽  
Author(s):  
Yali Wu ◽  
Dongguang Zhang
Keyword(s):  
Electric Field ◽  
Freeze Drying ◽  
Effective Diffusion ◽  
Specific Energy Consumption ◽  
Pulsed Electric Field ◽  
Drying Process ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Effective Diffusion Coefficients ◽  
Apple Tissue

The influence of pulsed electric field (PEF) on freeze-drying of apple tissue was investigated. The freeze-drying was performed with different parameters of PEF treatment, and PEF treatment on the drying characters, microstructure, rehydration ratio, effective diffusion coefficient and hardness of apple tissue were discussed separately. The results indicated that PEF utilization as a pretreatment of apples enhances the drying process. The drying time was shortened by 17.73% at most, specific energy consumption decreased by 24.74% at most, and the rehydration ratio was improved by 65.22% at most for PEF treatment samples respectively, compared with the untreated samples. The effective diffusion coefficients varied from 2.60 × 10−8 m2/s to 4.20 × 10−8 m2/s for PEF pretreated samples, and was 2.40 × 10−8 m2/s for untreated samples drying at 75°C, the hardness of the untreated apple tissue was about 144.4 N which was decreased to 39.5–115.0 N after PEF treatment. 

scholarly journals Evaluation of freezing pre-treatments for the lyophilisation of apple

2013 ◽  
Vol 5 (1) ◽  
pp. 56-68
Author(s):  
Tamás Antal ◽  
László Sikolya ◽  
Benedek Kerekes
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Ice Crystals ◽  
Freezing Rate ◽  
Slow Freezing ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried ◽  
Apple Slices

Abstract The effect of freezing rate on the quality of dried Jonagold and Idared (Malus domestica Borkh.) was studied. Apple slices underwent various pre-treatments, i.e. freezing in household freezer (freezing speed/rate: 0,5◦C/min), contact plate freezing (2◦C/min) and vacuumfreezing (3◦C/min). The quality of the freeze-dried product was then evaluated in terms of water activity (aw), hardness, color and rehydration. The texture and color experiments were carried out with texture analyser and colorimeter. The aw of apple slices was measured by aw apparatus. It was found that drying time was influenced by freezing rate. The freezing in household freezer (slow freezing rate) significantly reduces the duration of the freeze-drying process and consequently the process costs. The slow freezing rate allows the growth of large ice crystals at the beginning of the freeze-drying process; this fact should consequently lead to larger pores and injured cell walls and thus to shorter freeze-drying time. Quality of the freezing in household freezer product was assessed as higher than the quality of the other freezing pre-treated material. Slow freezing rate resulted softer texture and higher rehydration capacity than that of other pre-treated samples. In all cases, slow freezing speed lead to lower final moisture content, total color difference and water activity. Freeze-dried samples prepared with higher freezing rates (3◦C/min) were the most white in color because small pores, originated by sublimation of small ice crystals formed by fast freezing.

Drying characteristics and product quality of whole blueberry pulp in vacuum drying process

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lijuan Zhao ◽  
Yonghuan Li ◽  
Hui Xie ◽  
Jianliang Zhang ◽  
Zhonghua Wu
Keyword(s):  
Freeze Drying ◽  
Heating Temperature ◽  
Convective Drying ◽  
Vacuum Drying ◽  
Operating Pressure ◽  
Drying Process ◽  
Drying Time ◽  
Drying Characteristics ◽  
Freeze Dried ◽  
Monomeric Anthocyanins

Abstract A pilot-scale vacuum dryer with visualization system was used to study the drying characteristics of the whole blueberry pulp. The heating temperature, operating pressure and initial material thickness had significant effects on the drying characteristics and the retentions of total monomeric anthocyanins and vitamin C in dried blueberry powder (P < 0.05). According the heat transfer mode inside the material, the whole drying process could be divided into three periods: the boiling drying period, the convective drying period, and the conductive drying period. Most of water in the material was evaporated in the boiling and convective drying period. Considering the drying characteristics and dried product quality comprehensively, an optimal drying condition for whole blueberry pulp were: heating temperature 70 °C, operating pressure 1 kPa, and the initial material thickness 5 mm. It further compared the drying time, nutrients retention, hygroscopicity and microstructure of the product obtained by vacuum and vacuum freeze drying. The drying time of vacuum drying (1.2 h) was much shorter than that of vacuum freeze drying (44 h); the retentions of the total monomeric anthocyanins and vitamin C in dried blueberry powder of vacuum drying (67.9, 46.7%) were lower than that of vacuum freeze drying (79.0, 85.8%); while the hygroscopicity of vacuum dried powder was less than that of the freeze-dried product. The SEM images displayed that the surface of the vacuum-dried blueberry powder was porous, and the vacuum freeze-dried product was lamellar.

scholarly journals Impact of shelf temperature on freeze-drying process and porosity development

2018 ◽  
Author(s):  
M. M. Camacho ◽  
L. A. Egas-Astudillo ◽  
A. Silva ◽  
M. Uscanga ◽  
N. Martínez-Navarrete
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Gum Arabic ◽  
Drying Kinetics ◽  
Drying Process ◽  
Drying Time ◽  
Lower Porosity ◽  
The Impact ◽  
Shelf Temperature ◽  
Porosity Development

The freeze-drying kinetics and the superficial porosity development of grapefruit puree. The impact of biopolymers addition (gum Arabic and bamboo fiber) and to apply (40 ºC) or not shelf temperature (room temperature) was considered. To increase the shelves temperature during freeze-drying allowed to an important drying time reduction and doesn’t supposed a lower porosity related to the collapse development of the structure. Biopolymers do not affect the drying kinetics. From this results, biopolymers addition and to heat at least up to 40 ºC during grapefruit freeze-drying should be recommended. Keywords: freeze-drying; shelf temperature; drying kinetics; image analysis; pore size distribution.

scholarly journals Evaluation of Microwave Vacuum Drying as an Alternative to Freeze-Drying of Biologics and Vaccines: the Power of Simple Modeling to Identify a Mechanism for Faster Drying Times Achieved with Microwave

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Akhilesh Bhambhani ◽  
Justin Stanbro ◽  
Daniel Roth ◽  
Elizabeth Sullivan ◽  
Morrisa Jones ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Drug Product ◽  
Scale Up ◽  
Heat Transfer Process ◽  
Vacuum Drying ◽  
Drying Process ◽  
Drying Time ◽  
Capital Costs ◽  
Microwave Vacuum Drying ◽  
Fill Volume

AbstractVial-based lyophilization for biopharmaceuticals has been an indispensable cornerstone process for over 50 years. However, the process is not without significant challenges. Capital costs to realize a lyophilized drug product facility, for example, are very high. Similarly, heat and mass transfer limitations inherent in lyophilization result in drying cycle on the order of several days while putting practical constraints on available formulation space, such as solute mass percentage or fill volume in a vial. Through collaboration with an external partner, we are exploring microwave vacuum drying (MVD) as a faster drying process to vial lyophilization wherein the heat transfer process occurs by microwave radiation instead of pure conduction from the vial. Drying using this radiative process demonstrates greater than 80% reduction in drying time over traditional freeze-drying times while maintaining product activity and stability. Such reduction in freeze-drying process times from days to several hours is a welcome change as it enables flexible manufacturing by being able to better react to changes either in terms of product volume for on-demand manufacturing scenarios or facilities for production (e.g., scale-out over scale-up). Additionally, by utilizing first-principle modeling coupled with experimental verification, a mechanism for faster drying times associated with MVD is proposed in this article. This research, to the best of our knowledge, forms the very first report of utilizing microwave vacuum drying for vaccines while utilizing the power of simplified models to understand drying principles associated with MVD.

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