Freeze Drying
Source： | Date:
2010-10-24
| Hits:
Keywords:
Freeze Drying basic
The product to be freeze dried must be present in a deep frozen form. The freeze drying takes place under vacuum conditions below the "triple point" (6.2 mbar = 4.6 torr). Here water will only be present in two phases: ice and vapour. By adding energy to the ice it will sublimate (evaporate) directly into the vapour phase. The vapour is condensed immediately on vapour traps to maintain the vacuum.
Water vapour has easier access through any product cel structure compared to water penetrating the product mass to evaporate from the surface from the product as in the case in after drying methods. The gentle escape of water vapour in the freeze drying process leaves the product close to its original shape, and its taste and colour is preserved and there is no loss of aroma.
The vacuum and temperature used during the freeze drying operation depends on the product, its shape, water content, product structure and composition.
The product to be freeze dried must be present in a deep frozen form. The freeze drying takes place under vacuum conditions below the "triple point" (6.2 mbar = 4.6 torr). Here water will only be present in two phases: ice and vapour. By adding energy to the ice it will sublimate (evaporate) directly into the vapour phase. The vapour is condensed immediately on vapour traps to maintain the vacuum.
Water vapour has easier access through any product cel structure compared to water penetrating the product mass to evaporate from the surface from the product as in the case in after drying methods. The gentle escape of water vapour in the freeze drying process leaves the product close to its original shape, and its taste and colour is preserved and there is no loss of aroma.
The vacuum and temperature used during the freeze drying operation depends on the product, its shape, water content, product structure and composition.
Preparation of the products
Products for freeze drying falls into three basic categories:
Products for freeze drying falls into three basic categories:
- Liquids such as coffee and tea, juices and other extracts
- Individual quick frozen (IQF) product. Such a segment of or whole fruits, berries and vegetables as well as for instance shrimps or segments of fish and meat products.
- Combined products such as soup blochs, rice, dishes, baby purees, camping foods etc.
Freeze drying of liquids is the most complex. First the liquids must be treated to achieve the optimal solids content and colour. The preconcenttrated liquids must be frozen before the freeze drying. This is done either slowly on a CAB (Continuous Air Blast) freezer or more quickly on ROTA freezer. The frozen product is then granulated (milled) to obtain granules of the desired size before loading and weighing on trays before the freeze drying. The IQF products are loaded in frozen form directly by weight or volume on the trays before the freeze drying.
- Individual quick frozen (IQF) product. Such a segment of or whole fruits, berries and vegetables as well as for instance shrimps or segments of fish and meat products.
- Combined products such as soup blochs, rice, dishes, baby purees, camping foods etc.
Freeze drying of liquids is the most complex. First the liquids must be treated to achieve the optimal solids content and colour. The preconcenttrated liquids must be frozen before the freeze drying. This is done either slowly on a CAB (Continuous Air Blast) freezer or more quickly on ROTA freezer. The frozen product is then granulated (milled) to obtain granules of the desired size before loading and weighing on trays before the freeze drying. The IQF products are loaded in frozen form directly by weight or volume on the trays before the freeze drying.
Combined products are normally filled into trays with special plastic moulds that can withstand the extreme temperature changes. The product is then deep frozen in the moulds before freeze drying.
News
- 2024-06-08 > Exhibition Invitation |ACHEMA 2024, Germany
- 2019-06-15 > P-MECH CHINA 2019 YIBU BOOTH NO: N3B10a
- 2019-04-15 > YIBU will attend the 57th CIPM Exhibition held in Changsha in Hunan province
- 2018-12-28 > Actived carbon particle mesh belt dryer made for Ingrevity
- 2018-03-10 > big spin flash dryer and spray dryer delivery to pakistan and Italy customer on time
- 2017-12-29 > two sets high speed centrifugal spray dryers and three sets of drum dryre delivered to Indonesia
- 2017-08-24 > one set of LPG-100 spray dryer is delivered to America
- 2017-08-24 > Five layers mesh belt dryer is sucessfully delivered to Manila(Philippines)
- 2017-04-05 > Exhibition interpack 2017 in Dusseldorf In Germany
- 2016-11-23 > The 18th International Exhibition in Moscow
Products
-
ZDG Series vacuum vibrating dryer（Specially for lithium battery) -
YQJ Series Rotary Disc Dryer（Horizontal rotary disc dryer/Horizontal rotary disc paddle dryer) -
LDG Series Vertical single-conical ribbon mixer dryer -
HYD Series Rotary Calciner (calcination kiln) -
GWD Series high temperature belt calciner -
FWD Series Multi-functions filter washing drying machine -
FGBX series Sealed -Circuit Circulation Fluidizing Dryer -
HDT Series Post Hopper Mixer( Post Bin Blender)
