Freeze drying is a process that removes water from foods or other materials by freezing the product and then reducing pressure to allow the frozen water to sublimate from the solid to gas phase. It involves freezing, primary drying where the frozen water sublimates, and secondary drying to remove remaining unfrozen water. Freeze drying is useful for preserving foods, pharmaceuticals, and other temperature-sensitive materials as it avoids damaging heat and allows rehydration to the original state.
Dehydration process,
Typically used to preserve a perishable material or make the material more convenient for transport,
Mostly used for light food required by astronauts, hikers
Dehydration process,
Typically used to preserve a perishable material or make the material more convenient for transport,
Mostly used for light food required by astronauts, hikers
Freezing helps to Inhibit the growth of microorganisms hence help in preservation of foods. So, freezing is a very easy and effective method for the preservation of fruits and vegetables and to retain them for longer duration.
The process of freeze drying with greater emphasis on the uses in the fisheries food processing sector. The presentation shows the process involved and the different steps involved and the effect of the process on the food material.
The preservation of food by freezing has become a major industry.Preservation of a food by freezing occurs by several mechanisms. At
temperatures below 0°C there is a significant reduction in growth
rates for microorganisms and in the corresponding deterioration of
the product due to microbial activity.
Several freezing systems for food operate with direct contact between
the refrigerant and the product.
cryogenic freezer is direct contact freezer.
introduction, theory of drying, applications of drying, construction & working about fluidised bed dryer,use of tray dryer,construction about vacuum dryer, construction & working about drum dryer, construction about spray dryer
spray drying is technology widely used in milk powder and coffee powder manufacturing industry because of its working principle and technology involved..
Freezing helps to Inhibit the growth of microorganisms hence help in preservation of foods. So, freezing is a very easy and effective method for the preservation of fruits and vegetables and to retain them for longer duration.
The process of freeze drying with greater emphasis on the uses in the fisheries food processing sector. The presentation shows the process involved and the different steps involved and the effect of the process on the food material.
The preservation of food by freezing has become a major industry.Preservation of a food by freezing occurs by several mechanisms. At
temperatures below 0°C there is a significant reduction in growth
rates for microorganisms and in the corresponding deterioration of
the product due to microbial activity.
Several freezing systems for food operate with direct contact between
the refrigerant and the product.
cryogenic freezer is direct contact freezer.
introduction, theory of drying, applications of drying, construction & working about fluidised bed dryer,use of tray dryer,construction about vacuum dryer, construction & working about drum dryer, construction about spray dryer
spray drying is technology widely used in milk powder and coffee powder manufacturing industry because of its working principle and technology involved..
This presentation was delivered by Dr. A at the 2011 Annual Conference of the Southern Region American Society for Horticulture Science at Corpus Christi, TX.
Presentation during the Bureau of Agricultural Research (BAR) Seminar Series on July 23, 2016 at RDMIC Bldg., cor. Visayas Ave., Elliptical Rd., Diliman, Quezon City
This color atlas of poultry diseases .This is very useful guide for poultry farmers & poultry practicing professionals.The atlas contains colour photographs demonstrating the overall pathology of birds. The book includes more than 50 diseases from avian infectious pathology and a similar number from non-infectious pathology.There are both classic and well known diseases and new and little known diseases. The book is designed for veterinarians, veterinary students, poultry farmers and poultry specialists.
To get more free guides and literature and books please visit www.growelagrovet.com
Broiler Farming Management Guide is designed to help Aviagen’s customers achieve optimum performance from their birds. While not intended to provide definitive information on every aspect of management, this manual does draw attention to important issues that if overlooked or inadequately addressed may depress flock performance. The objective of this manual is to provide management techniques that help growers achieve good overall bird performance from day one through to processing while promoting bird health and welfare.
Aviagen applies a balanced approach to genetic progress, concentrating on commercial traits such as growth rate, feed conversion ratio, livability and meat yield, while improving bird welfare in areas such as leg health, cardiovascular fitness and robustness.
Achieving the genetic potential of the birds depends on three key factors:
• Management to provide birds with their required environment.
• A dietary regimen that offers nutrients in the appropriate profile.
• Effective biosecurity and disease control programs.
These three sectors, environment, nutrition and health, are interdependent. A shortfall in anyone will bring negative consequences to the others and if any one of these elements is sub-optimal, broiler performance will suffer.In reality, the guidance of a manual such as this cannot wholly protect against performance variations that may occur for a wide variety of reasons. While every attempt has been made to ensure the accuracy and relevance of the information presented, Aviagen accepts no liability for the consequences of using this information for the management of chickens. Information presented in this manual combines data derived from internal research.
Broiler poultry farming is a lucrative business. Generally highly meat productive birds or poultry breeds are called broiler poultry. But broiler chicken is a special species of poultry, which is a great secret. Only four countries of the world knows about this secret and they supply and maintain all the demand of broiler chickens. Broilers are like other common poultry birds. But this broiler is made in a scientific way for producing more meat in a short time. Basically, broilers are only for meat production.
A good poultry health management is an important component of poultry production. Infectious disease causing agents will spread through a flock very quickly because of the high stocking densities of commercially housed poultry.
For poultry health management to be effective a primary aim must be to prevent the onset of disease or parasites, to recognize at an early stage the presence of disease or parasites, and to treat all flocks that are diseased or infested with parasites as soon as possible and before they develop into a serious condition or spread to other flocks. To be able to do this it is necessary to know how to recognize that the birds are diseased, the action required for preventing or minimising disease and how to monitor for signs that the prevention program is working.
Poultry production can be divided into four sectors:
1. industrial and integrated, 2.commercial high bio-security, 3. commercial low bio-security, 4. village, and family or backyard poultry. The focus here is largely on sectors 3 and 4 but there may be some overlap.
‘Family poultry’ as defined by the International Network for Family Poultry Development, covers sectors 3 and 4 which encompass small - scale poultry production.
There are numerous poultry handbooks which cover sectors 2 and 3, but this hand book has attempted, in two manuals, to cover mainly sector 3 while not ignoring the great importance of bio-security particularly in the face of highly pathogenic avian influenza (H5N1). It is envisaged that, given time, some producers, now in sector 3 may move into sector 2.
The two manuals are pitched at two different levels.
The Trainer’s (instructor) manual assumes that the trainer has qualifications and/or experience in a branch of agricultural science but not necessarily in poultry production. Some of the material included is beyond that necessary to give an initial course in poultry production but may be useful as the farmer progresses from sector 3 to sector 2. The trainee’s manual has numerous illustrations and is aimed at a lower level than for the trainer.
The farmer may be interested in starting a poultry enterprise is already producing poultry in a small - scale commercial or semi-commercial (opportunistic) situation but would like to make poultry farming more permanent. The course will allow the farmer to increase his/her knowledge and skills and to become aware of a number of important issues (e.g. managing the environment, disease surveillance) of his/her enterprise.
In order to minimise repetition, there is some material in the trainee’s manual that is not in the trainer’s manual. Trainers should familiarise themselves thoroughly with both manuals.
The third manual is for the millions of families, worldwide, in low – income,
developing countries who keep backyard poultry, mainly unmanaged, with few inputs, but nevertheless are of great importance by providing, some security, income and high – quality protein. It is hoped that this manual will make families aware of the possibility of improving output with a minimum of input.
Much of the information has been taken from a range of sources as well as the author’s own experience of working in several developing countries over 25 years.
Ideally, there should be a small-scale demonstration unit or a poultry farm available so that the trainees can see, first hand, and better understand the main points in these manuals and observe how commercial poultry production should be practised.
Definition of drying
Importance of drying
Difference between drying and evaporation
Equipments
References
Definition
A stabilizing process in which a substance is first frozen and then the quantity of the solvent is reduced, first by sublimation (primary drying stage) and then desorption (secondary drying stage) to values that will no longer support biological activity or chemical reactions.
History
Freeze drying was first actively developed during WORLD WAR II transport of serum.
The main aim was to store the products without refrigeration and to remove moisture from thermolabile compounds.
Atlas in 1961 built 6 production freeze drying cabinet for Nestle group in Germany, Holland.
Principle
Lyophilization is carried out using a simple principle of physics sublimation. Sublimation is the transition of a substance from the solid to the vapour state, without first passing through an intermediate liquid phase.
Lyophilization is performed at temperature and pressure conditions below the triple point, to enable sublimation of ice.
The entire process is performed at low temperature and pressure by applying vacuum, hence is suited for drying of thermolabile compounds.
The concentration gradient of water vapour between the drying front and condenser is the driving force for removal of water during lyophilization.
The presentation consists of the introduction, basic terms, and different types of ideal cycles of refrigeration,
1. Introduction to refrigeration
2. Necessity and applications
3. Unit of refrigeration and C.O.P.
4. Types of ideal cycles of refrigeration
a) Bell Coleman cycle
b) Open and dense air systems
5. Boot strap Air refrigeration system
Lyophilization or freeze drying is a process in which water is removed from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapor without passing through a liquid phase. The process consists of three separate, unique, and interdependent processes; freezing, primary drying (sublimation), and secondary drying (desorption).
The advantages of lyophilization include:
Ease of processing a liquid, which simplifies aseptic handling
Enhanced stability of a dry powder
Removal of water without excessive heating of the product
Enhanced product stability in a dry state
Rapid and easy dissolution of reconstituted product
Disadvantages of lyophilization include:
Increased handling and processing time
Need for sterile diluent upon reconstitution
Cost and complexity of equipment
The lyophilization process generally includes the following steps:
Dissolving the drug and excipients in a suitable solvent, generally water for injection (WFI).
Sterilizing the bulk solution by passing it through a 0.22 micron bacteria-retentive filter.
Filling into individual sterile containers and partially stoppering the containers under aseptic conditions.
Transporting the partially stoppered containers to the lyophilizer and loading into the chamber under aseptic conditions.
Freezing the solution by placing the partially stoppered containers on cooled shelves in a freeze-drying chamber or pre-freezing in another chamber.
Applying a vacuum to the chamber and heating the shelves in order to evaporate the water from the frozen state.
Complete stoppering of the vials usually by hydraulic or screw rod stoppering mechanisms installed in the lyophilizers.
There are many new parenteral products, including anti-infectives, biotechnology derived products, and in-vitro diagnostics which are manufactured as lyophilized products. Additionally, inspections have disclosed potency, sterility and stability problems associated with the manufacture and control of lyophilized products. In order to provide guidance and information to investigators, some industry procedures and deficiencies associated with lyophilized products are identified in this Inspection Guide.
It is recognized that there is complex technology associated with the manufacture and control of a lyophilized pharmaceutical dosage form. Some of the important aspects of these operations include: the formulation of solutions; filling of vials and validation of the filling operation; sterilization and engineering aspects of the lyophilizer; scale-up and validation of the lyophilization cycle; and testing of the end product. This discussion will address some of the problems associated with the manufacture and control of a lyophilized dosage form.
Freezing has been successfully employed for the long-term preservation of many foods, providing a significantly extended shelf life.
The process involves lowering the product temperature generally to -18 °C or below.The extreme cold simply retards the growth of microorganisms and slows
down the chemical changes that affect quality or cause food to spoil.
During freezing the cellular solution present in the food matrix is cooled to its initial freezing point, and further cooling causes the water molecule to
separate, forming ice crystal.
The migration of water molecules during crystallization led to an increase in osmotic pressure, further enhancing the water permeability of the cell membranes. This transport of water molecules, if not controlled, can eventually affect the microstructure of the frozen produce.
The freezing process occurs in two successive steps, i.e,
” NUCLEATION” and “CRYSTAL GROWTH”.
The all the content in this profile is completed by the teachers, students as well as other health care peoples.
thank you, all the respected peoples, for giving the information to complete this presentation.
this information is free to use by anyone.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Thesis Statement for students diagnonsed withADHD.ppt
Freeze drying ppt
1. -: Presented by :-
Monika K. Tambakhe
Dr. P.A. Pawar
University Department of Chemical Technology, Sant Gadge baba
Amravati University ,Amravati. Maaharashtra,INDIA.444602.
Email id-mk2tambakhe@gmil.com
papawar40@rediffmail.com
2. INTRODUCTION
Freeze drying is a relatively recent method of preserving food.
Although it is not widely used in the food industry due to high
operation costs, new improvements such as adsorption,
fluidization, and microwave have been researched in order to
reduce costs.
It is the most important technique to dry coffee, enzymes, food
ingredients, high value foods.
This process could be considered as a valuable alternative to
preserve foods.
3. INTRODUCTION
Stabilization of enzymatic systems, new ingredients in the
field of functional foods, and exotic foods are examples of new
applications of this technology.
In a general way, freeze-drying or lyophilization, is the process
of removing water from a product by sublimation and
desorption.
Sublimation is the transformation of ice directly into a gas
without passing through a liquid phase. Sublimation occurs
when the vapor pressure and the temperature of the ice
surface are below those of the triple point (4.58 mm Hg, 0 ºC),
as shown in the pressure-temperature phase diagram of pure
water(Figure 1).
4. INTRODUCTION
Figure No.1 - Pressure-temperature phase diagram of pure
water and zones of processes for phase changes
5. INTRODUCTION
In short, freeze drying is a multiple operation in which the
material to be stabilized is-
1. Frozen hard by low-temperature cooling
2. Dried by direct sublimation of the frozen solvent and by
desorption of the sorbed or bound solvent , generally under
reduced pressure.
3. Stored in the dry state under controlled conditions.
6. INTRODUCTION
However, freeze drying is an expensive form of dehydration
for foods because of the slow drying rate and the use of
vacuum. The cost of processing is offset to some extent by
the absence of any need for refrigerated handling and
storage.
Increasingly, freeze drying is used for dehydrating foods
otherwise difficult to dry, such as coffee, onions, soups, and
certain sea foods and fruits. Freeze drying is also increasingly
employed in the drying of pharmaceutical products.
8. HISTORY-
The history of freeze drying goes back to the ancient Inca’s,
who preserved their food stuff by freezing it in the mountains
in winter time. At the same time the frozen water is removed
through the low vapor pressure of the water in the
surrounding air at those high altitudes.
Of course this process was rather slow, but during the drying
process the quality of the food was maintained due to its
frozen state. Once dried the food materials like potatoes and
vegetables showed a remarkably increased quality over time.
9. HISTORY-
Especially the need for improving shelf life of
pharmaceuticals like penicillin and the preservation of blood
plasma in war time was a drive for the development of the
modern tray-type Lyophilizer as it is still used in many
industries today.
Another catalyst for the development of the freeze dry
technology was the surplus of coffee in countries like Brazil in
the late 30’s of the previous century.
10. HISTORY-
Also here the tray-type freeze dryer was used for the
sublimation of the water from the frozen coffee granules.
Brand names like Nescafe were founded at that time. Instant
coffee is now the most well-known freeze dried product.
After the war period the technology emerged into its current
popularity for the drying of many different temperature
sensitive materials like pharmaceuticals and food materials.
There exist already 400 different freeze dried food materials
alone.
11. FREEZE DRYING PROCESS -
Freeze drying is a process by which a solvent (usually
water) is removed from a frozen foodstuff or a frozen
solution by sublimation of the solvent and by desorption of
the sorbed solvent (nonfrozen solvent), generally under
reduced pressure. The freeze drying separation method
(process) involves the following three stages:
(a) the freezing stage,
(b) the primary drying stage, and
(c) the secondary drying stage.
12. FREEZE DRYING PROCESS -
Figure No.2 – Diagram of a material on a tray during freeze
drying.
The variable X denotes the position of the sublimation
13. FREEZING STAGE-
The freezing stage represents the first separation step
in the freeze drying process, and the performance of the
overall freeze drying process depends significantly on
this stage. The material system to be processed (e.g., gel
suspension, liquid solution, or foodstuff) is cooled down
to a temperature (this temperature depends on the
nature of the product) that is always below the
solidification temperature of the material system.
The objective of the freezing stage is to freeze most of
the water originally present in the product for its
posterior sublimation.
14. PRIMARY DRYING STAGE
After the freezing stage, the drying chamber where the product
is placed is evacuated and the chamber pressure is reduced to a
value that would allow the sublimation of solvent (water) to take
place in the primary drying stage.
When the water molecules sublime and enter the vapor phase,
they also keep with them a significant amount of the latent heat
of sublimation (2840 kJ/kg ice) and thus the temperature of the
frozen product is again reduced.
If there is no heat supplied to the product by a heat source, then
the vapor pressure of the water at the temperature of the product
reaches the same value as that of the partial pressure of the water
vapor in the drying chamber; therefore, the system reaches
equilibrium and no additional water sublimation from the product
would occur.
15. PRIMARY DRYING STAGE
The water vapor produced by the sublimation of the frozen
water in the frozen layer and by the desorption of sorbed (non
frozen) water in the dried layer during the primary drying
stage travels by diffusion and convective flow through the
porous structure of the dried layer and enters the drying
chamber of the freeze dryer. (It should be noted that most of
the water removed during the primary drying stage is
produced by sublimation of the frozen water in the frozen
layer.)
The time at which there is no more frozen layer is taken to
represent the end of the primary drying stage.
16. SECONDARY DRYING STAGE
The secondary drying stage involves the removal of water that
did not freeze (sorbed or bound water). In an ideal freeze drying
process, the secondary drying stage starts at the end of the primary
drying stage.
In the secondary drying stage, the bound water is removed by
heating the product under vacuum; the heat is supplied to the
product usually by conduction, convection, or radiation. The
following product temperatures are usually employed: (a) between
10 and 35 C for heat sensitive products and (b) 50 C or more for
less-heat-sensitive products.
The residual moisture content in the dried material at the
end of the secondary drying stage, as well as the temperature
at which the dried material is kept in storage, are critical
factors in determining product stability during its storage life.
17. HEAT AND MASS TRANSFER IN FREEZE-DRYING -
Rate of heat transfer-
There are three methods of transferring heat to the
sublimation front.
1. Heat transfer through the frozen layer
2. Heat transfer through the dried layer
3. Heating by microwaves
Heat SourceCondenser
Mass
Transfer
Heat
Transfer
Frozen
Portion
part
Dry
Portion
part
18. Rate of mass transfer-
When heat reaches the sublimation front, it raises the
temperature and the water vapour pressure of the ice.
Vapour then moves through the dried food to a region of
low vapour pressure in the drying chamber.
The factors that control the water vapour pressure gradient
are:
the pressure in the drying chamber
the temperature of the vapour condenser, both of
which should be as low as economically possible.
the temperature of ice at the sublimation front, which
should be as high as possible, without melting.
19. (a)Heat transfer through frozen layer
(b)Heat transfer from hot surfaces through dry layer
(c)Heat generated in ice by microwaves
20. COMPONENTS OF A FREEZE-DRYER -
Figure: Components of freeze dryer
21. COMPONENTS OF A FREEZE-DRYER -
The drying chamber, in which the sample is placed and
heating/cooling takes place, must be vacuum tight and with
temperature controlled shelves.
The condenser must have sufficient condensing surface and
cooling capacity to collect water vapor released by the
product. As vapors contact the condensing surface, they give
up their heat energy and turn into ice crystals that will be
removed from the system. A condenser temperature of -65 ºC
is typical for most commercial freeze dryers.
The vacuum pump removes non-condensable gases to achieve
high vacuum levels (below 4 mm Hg) in the chamber and
condenser.
The heat source provides the latent heat of sublimation, and
its temperature may vary from –30 to 150 ºC .
22. In the freeze drying plant, three process sections are
especially energy consuming.
Process section 1 involves the freezing of the wet product. As
this is normally considered one of the preparatory steps
before the freeze drying proper, we will concentrate on the
other two that take place in the freeze drying cabinet .
Process section 2 involves the controlled supply of heat to
the product to cover requirements for the sublimation and
desorption processes.
Process section 3 involves the removal from the freeze
drying chamber of the vast volumes of water vapor released
drying the sublimation and desorption processes. Of these
three process sections, removal of the water vapour always
consumes the largest amount of energy. The efficiency of
water vapor removal, the vapor trap system, therefore has a
decisive effect on the total energy consumption of the freeze
drying plant.
FREEZE DRYING PLANTS AND EQUIPMENT
-
23. 1. Pilot freeze drying
2. Industrial freeze drying
a. Tray and Pharmaceutical Freeze Dryers
b. Multibatch Freeze Dryers
c. Continuous Freeze Dryers
d. Tunnel Freeze Dryers
e. Vacuum-Spray Freeze Dryers
FREEZE DRYING PLANTS AND
EQUIPMENT -
24. 1. PILOT FREEZE DRYING
Freeze drying pilot units appropriate for use in the
pharmaceutical and food industries, as well as in the
laboratory, are in high demand because they are used to
explore possibilities for the preservation of labile products,
especially with those of biological origin.
They can freeze-dry batches consisting of from 2 to 20 kg of
frozen product.
The unit consists of
(a) a freezing fluid system that can be sent to the heat
exchanger in the section of the condenser or into the
refrigeration coils for product freezing,
(b)a heating circuit (silicon oil is the heating fluid) for plate
heating and defrosting of the condenser, and
(c) a vacuum system for evacuating air from the apparatus
before and during drying.
26. 2. INDUSTRIAL FREEZE DRYING -
(a)Tray and Pharmaceutical Freeze Dryers:
By far the largest number of the industrial freeze dryers
in operation is of the vacuum batch type with freeze drying of
the product in trays. There are two main types, depending on
the type of condenser used. In the first type, the condenser
plates are alongside the tray heater assembly and in the same
chamber; in the second type the condenser is in a separate
chamber joined to the first by a wide, in general, butterfly
valve. This latter type of plant is always used in pharmaceutical
industries, but it can also be used for the freeze drying of foods.
27. (b)Multibatch Freeze Dryers :
The freeze drying process in a batch plant is normally
program controlled to minimize the drying time and to
maximize the production of the plant. With a single-batch
plant the load on the various systems will be very variable
throughout the drying cycle.
The optimal utilization of resources will not be possible in a
single-cabinet batch plant.
The extent of this disadvantage can be eliminated when an
industrial freeze drying plant is built with a number of batch
cabinets. This makes possible the simultaneous production of
different products, which increases the operation flexibility of
the plant .
A large number of industrial freeze drying plants operate
today in this way as multi-cabinet batch plants .
29. (c)Continuous Freeze Dryers :
Recent years have shown a growing interest in freeze
drying plants operating with a continuous flow of material
through the process. Particularly in industries working with a
single standardized product and the preparation of the
product is by a continuous process, such plants are really
profitable.
They give continuity in processing throughout and constant
operating conditions that are easily controlled, and they
require less manual operation and supervision.
Continuous freeze dryers are used for freeze drying of
product in trays and for freeze drying of agitated bulk
materials.
31. (d)Tunnel Freeze Dryers :
Large commercial plants for processing cottage cheese and coffee
have been built up in this way. The tunnel freeze dryers have the
same advantages of plant capacity utilization that can be achieved as
in multi-batch plants, but the flexibility for simultaneous production
of different products or in switching from one product to another is
lacking.
In the tunnel type of freeze dryer,
the process takes place in a large
vacuum cabinet into which the
tray-carrying trolleys are loaded at
intervals through a large vacuum
lock at one end of the tunnel and
discharged similarly at the other
end.
33. (e)Vacuum-Spray Freeze Dryers:
This dryer has been developed for coffee extract, tea
infusion, or milk. The product is sprayed from a single jet
upward or downward in a cylindrical tower of 3.7m diameter
by 5.5m high. The liquids solidify into small particles by
evaporative freezing The whole plant operates under a
vacuum of about 67 Pa. Frozen particles obtained by spraying
into a vacuum are about 150 mm in diameter and lose about
15% moisture in the initial evaporation. There is no sticking of
these particles.
36. THE MANUFACTURING PROCES -
Raw Materials :
• Some foods are extremely well-suited to the freeze-
drying process; others do not fare so well. Liquids, thin
portions of meat, and small fruits and vegetables can be
freeze-dried easily. Coffee is the most common freeze-
dried liquid.
• Thick portions of meat and larger, whole vegetables
and fruits cannot be freeze dried with any success
Testing and preparation:
• The food is first checked for contamination and purity.
• Some kinds of food, like seafood and meats, must be
cooked before freeze drying.
37. THE MANUFACTURING PROCES -
Freezing : Temperature is as low as -40 F (-40 C). In this
extremely cold temperature, the food is quickly frozen.
Drying : The carts are wheeled out of the cold room and into a
vacuum drying chamber. In a large plant, there may be 20 to 30
drying chambers in operation at any time. The drying procedure
involves a sublimation process.
Sizing and blending :Some food pieces may be ground to a
smaller size or may be reduced to a powder. Others may be
screened to separate them by size. Two or more different
products may also be blended together to meet a customer's
specific specifications.
Packing :Freeze-dried foods must be sealed in airtight
containers to prevent them from absorbing moisture from the
air. Several types of containers may be used: plastic laminated
foil pouches, metal and plastic cans, or metal and fiber drums for
bulk packaging. Some freeze-dried food is vacuum packed, in
which the air is evacuated from the container before sealing.
38. QUALITY CONTROL -
Each food has different processing, storage, and
rehydration requirements.
At large freeze-drying facilities, electronic
microprocessors regulate the times, temperatures, and
pressures throughout each step of the process.
A central computer collects this data, analyzes it using
statistical quality control methods, and stores it for
later reference.
This assures that the food sent out to the public for
consumption has been through a strictly controlled
process that meets government guidelines and varies
only slightly from batch to batch
39. Figure :Effect of freezing-rate and heating temperature on freeze-drying
rate of “guacamole”
INFLUENCE OF PARAMETERS -
40. INFLUENCE OF PARAMETERS -
1. Freezing rate : Influence on the ice configuration and thus on
the final structure of the freeze-dried product
2. Heat flux : to reduce drying rate. However, if the drying
proceeds too rapidly (high heat flux), the product may melt,
collapse or can be blown out of the container Excessive heat
may cause the dry cake to char or shrink.
3. Chamber pressure: Chamber pressure affects the transport
properties, thermal conductivity and water vapor diffusivity.
4. Temperature: affecting the quality of freeze-dried products .
Maintaining low temperatures during primary drying will
reduce aroma losses. If the temperature of ice in the condenser
is higher than product’s temperature, water vapor will tend to
move toward the product, and drying will stop.
41. Freeze drying is costly because of the long drying times
involved; this factor has hindered the application of the
technique to drying of materials in bulk.
Fixed cost -The average fixed cost is given by the ratio of
the annual fixed cost to the annual capacity.
Running cost - The running cost consists of labor and
utilities costs. The utilities cost can be estimated from a
heat and energy balance for 1-kg water undergoing
freezing, sublimation, condensation, and melting.
FREEZE DRYING COSTS -
45. Freeze dried Garlic- Freeze Dried Turmeric-
Freeze Dried Red Chilly and Green Chilly-
46. APPLICATIONS OF FREEZE DRYING-
Biggest market for freeze-drying is the food industry.
Freeze-dried food is used by hikers, hunters, astronauts, the
military, as well as being used in the food industry for
dehydrated soups and meals for consumers in the
supermarket. The largest application is freeze-dried coffee.
freeze-dried microorganisms- frequently used for
fermentation reactions , used in bioconversion reactions and
stored for research.
In the pharmaceutical industry – For saving
many medicines lives and for life saving substance that is
blood.
47. Freeze dried fruit powders/ slices dices are often
used:
for making many delicious food products like Fruit
drinks, ice creams, thick shakes, yogurt and other
desserts when fresh fruits are not available.
used to make soft candy, toffee and hard candy.
making instant juice mixes, flavoring baby / infant
foods, preparing food premixes, and range of bakery
products.
use in rich cream fillings, chocolate products and
baked goods as well as in cereals and fruit bars.
FREEZE DRIED FOOD PRODUCT APPLICATIONS -
48. FREEZE DRIED FOOD PRODUCT APPLICATIONS
Fruit granules are used in products where the fruit content
desired also texture and crunchiness is required.
Freeze dried spices and vegetable used in manufacturing of
instant vegetable noodles, soups, snacks and different kinds of
fast food.
Freeze dried food is use for making pet foods.
freeze dried soup
49.
50. ADVANTAGES OF FREEZE DRYING-
1. Retain taste, smell and texture –
2. Fewer loss of Nutrient –
3. Reduce weight –
4. Fewer Preservatives –
5. Extended Shelf Life-
6. The Safety Advantage-
7. Rapid Rehydration Advantage-
Rehydration
52. convenient method for drying those decomposable
products (mostly pharmaceuticals, e.g., plasma, vaccines,
antibiotics, sera, and growth hormones) that cannot be
stabilized in any other way or that show markedly improved
quality for a rather high average cost (coffee, mushroom s,
diced chicken, and others )
suitable for high-value products with specific biological or
phytochemical properties.
CONCLUSION-