Encapsulation is a fundamental concept in object-oriented programming (OOP) that binds together the data and the methods that manipulate the data, and that keeps both safe from outside interference and misuse ¹ ². The key characteristics of encapsulation are ¹ ²:
- Data Hiding: The implementation details of a class are hidden from the outside world.
- Abstraction: The class exposes only the necessary information to the outside world while hiding its internal details.
- Encapsulation of Data: The data is encapsulated and can only be accessed through the methods of the class.
- Code Reusability: Encapsulation makes the code reusable and easy to maintain.
- Increased Flexibility: Encapsulation provides flexibility in terms of implementation and modification of the class.
- Testing Code is Easy: Encapsulated code is easy to test for unit testing.
- Freedom to Programmer: Encapsulation gives the programmer the freedom to implement the details of the system without affecting the other parts of the program.
2. INTRODUCTION
➢ Nutraceutical is defined as “any non-toxic food (or a part of
food) that plays a role in maintaining well- being, enhancing
health, modulating immunity and thereby preventing as well as
treating specific diseases”.
➢ENCAPSULATION is defined as “a process to entrap active
agents within a carrier material (wall material)”.
➢Microencapsulation is defined as technology of packaging
solids, liquids and gaseous material in a miniature, sealed
capsules that can release their content at control rates under
the influences of specific conditions.
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3. FUNDAMENTAL CONSIDERATION
➢ Generally micro particles consist of two components:
a) Core Material
The material to be coated. It may be liquid or solid or gas.
Liquid core may be dissolved or dispersed material.
➢ Composition of core material:
Drug or active constituent, additive like diluents stabilizers
b) Coating Material
➢ Inert substance which coats on core with desired
thickness.
➢ Composition of coating:
• Inert polymer
• Plasticizer
• Colouring agent
• Resins, waxes and lipids
• Release rate enhancers or retardants
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6. -Mononuclear
-Polynuclear
-Matrix type
Mononuclear capsules
are the most common type
of microcapsule,
consisting of a core
surrounded by the shell,
whereas polynuclear
capsules have many cores
enclosed within a single
shell. Conversely, in
matrix-type
microcapsules, the core
material is distributed
homogeneously into the
shell material.
MORPHOLOGY OF
ENCAPSULATION
7. REASONS FOR ENCAPSULATION
The core must be isolated from its surroundings, as
1. To protect reactive substances from the environment,
2. To convert liquid active components into a dry solid system,
3. To separate incompatible components for functional reasons,
4. To protect the immediate environment of the microcapsules from the active
components
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8. REASONS FOR ENCAPSULATION
CONT..
To control the rate at which it leaves the microcapsule, as
1. To control release of the active components for delayed (timed) release or
long-acting (sustained) release,
2. The problem may be as simple as masking the taste or odour of the core,
3. To increase bioavailability,
4. Protects the GIT from irritant effects of the drug,
5. Extension of duration of activity for an equal level of active agent
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10. MOLECULAR INCLUSION
β cyclodextrins are enzymatically modified
starch molecules, which can be made by the
action of cyclodextrin glucosyltransferase
upon starch. After cleavage of starch by the
enzyme, the ends are joined to form a
circular molecule.
The inner hydrophobic cavity of β
cyclodextrin is torus shaped (like a
doughnut), where core material can fit and
released after heat treatment.
cyclodextrins are mainly used solubilizing
agents to increase water-solubility of
lipophilic compounds. E.g. polyphenol
(phlorotannin) from fish oils. Cyclodextrins
can be used to mask bitter components in
orange juice or grape fruit juice (limonin and
11. COACERVATION
TThe term "coacervate" is
sometimes used to refer to
spherical aggregates of
colloidal droplets held
together by hydrophobic
forces
TThis type is the phase
separation of one or many
hydrocolloids ( gel formation
in presence of water) in the
initial solution and the
subsequent deposition of the
newly formed coacervate
phase around the active
ingredient suspended or
emulsified in the same
reaction media.
IIt is used to encapsulate
flavor oil and can also be
adapted for the encapsulation
of fish oils, nutrients, vitamins,
preservatives and enzymes.
12. COACERVATION CONT..
➢ A unique and promising microencapsulation technology because of the very
high payloads achievable (up to 99%) and the controlled release
possibilities based on mechanical stress, temperature or sustained release.
➢ Mechanism: phase separation of one or many hydrocolloids from the initial
solution and the subsenquent deposition of the newly formed coacervate phase
around the active ingredient suspended or emulsified in the same reaction
media.
➢ The hydrocolloid shell can then be crosslinked using an appropriate chemical
or enzymatic crosslinker, if needed.
➢ A very large number of hydrocolloid systems has been evaluated for
coacervation microencapsulation but the most studied and well understood
coacervation system is probably the gelatin/gum arabic system.
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13. COACERVATION IN GELATINE/GUM
ACACIA
➢ dissolving gelatin and gum arabic at a 1:1 ratio and at a 2–4% of each
polymer to make o/w emulsion
➢ adjusting the pH from neutral to about 4 under turbulent conditions in a stirred
vessel at >35°C, (above the gelation temperature of gelatin)
➢ creating three immiscible phases (oil, polymer-rich, and polymer-poor phase),
➢ deposition of polymer rich phase droplets on the emulsion surfaces because
of interfacial sorption.
• Alternatively, complex coacervation can be induced by dilution instead of pH
adjustment
• oil is emulsified in a 8–11% (w/w) gelatin solution,
• followed by addition of gum arabic and dilution water.
• Upon cooling well below 35°C , the deposited gelatin and thus the shell will
solidify. 13
15. CO-CRYSTALLISATION
The nutraceuticals which include polyunsaturated fatty
acid (PUFA), dietary fibres, polyphenols, spices,
prebiotics, probiotics and vitamins are the natural food
sources. However, these nutraceuticals have high
hydrophobicity and are sensitive to external agents such
as air, light and oxidative enzymes which constitute a
serious problem for their bioavailability. Co-crystallization
is a technique most frequently used when the main aim
is to enhance the solubility. Cocrystals are based on
crystal engineering approach which involves the concept
of forming new solids (polymorph/solvates and
cocrystals/salts) involving non covalent interactions. Thus
nutraceutical cocrystals are multi-component solid-state
assemblies formed between a nutraceutical and a
cocrystal former of GRAS status bound together in the
crystal lattice by any type or combination of non-covalent
intermolecular interactions.
16. SPRAY DRYING
A substance to be encapsulated (the load) and
an amphipathic carrier (usually some sort of
modified starch) are homogenized as a
suspension in water (the slurry). The slurry is
then fed into a spray drier, usually a tower
heated to temperatures well over the boiling
point of water.
As the slurry enters the tower, it is atomized.
Partly because of the high surface tension of
water and partly because of the
hydrophobic/hydrophilic interactions between the
amphipathic carrier, the water, and the load, the
atomized slurry forms micelles.
The small size of the drops (averaging 100
micrometers in diameter) results in a relatively
large surface area which dries quickly. As the
water dries, the carrier forms a hardened shell
17. SPRAY DRYING
➢ One of the oldest processes to encapsulate active agent
➢ Materials used – Modified starch, maltodextrin, gums
• Preparation of dispersion
• Homogenization of the dispersion
• Atomization of the in feed dispersion
• Dehydration of the atomized particles
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18. SPRAY COOLING
Spray chilling is the process of
solidifying an atomized liquid
spray into particles. Also referred
to as spray cooling, spray
congealing, or prilling, this
process is suitable for making
particles from a few microns to
several millimeter. A molten
matrix with low melting point
containing a bioactive compound
is atomized through a nozzle into
a vessel. It is based on injection
of cold air into the vessel to
enable solidification of the gel
particle rather than on hot air
which dries the droplet into fine
powder particle as in spray
drying.
19. SPRAY-COOLING CONT..
➢ The spray cooling is a technique with possibility to achieve high yields and it
can be run in both continuous and batch processing modes.
➢ In case of spray-chilling, the particles are kept at a low temperature in a set-up
similar to the fluidized bed spray granulation.
➢ The difference between these two techniques is the melting point of lipids. In
spray chilling it is in range of 34–42°C and for spray cooling temperature is
higher.
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20. SPRAY-CHILLING OR SPRAY-
COOLING
➢ To produce lipid-coated active agents.
➢ The active agent could be dissolved in lipids, present as dry particles or
present as aqueous emulsions.
➢ Firstly, droplets of molten lipid(s) are atomized into a chilled chamber (e.g.,
via nozzle, spinning disk or (centrifugal) co-extrusion), which results in
solidification of the lipids and finally their recovery as fine particles.
➢ The initial set-up of spray cooling is quite similar to spray-drying but no water
is evaporated here
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22. LIPOSOME
A liposome can be defined as an artificial lipid
vesicle that has A bilayer phospholipids
arrangement with the head groups oriented
towards the interior of the bilayer and the
acyl group towards the exterior of the
membrane facing water
A unique property of liposomes is the
targeted delivery of their content in specific
parts of food stuffs. Liposomes can also be
used to deliver the encapsulated ingredient at
a specific and well-defined temperature.
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FLUIDIZED BED TECHNOLOGY
Wurster coating, synonymous with fluid bed
microencapsulation, is the encapsulation of
discrete particles in a fluidized bed using
differential air flow to create a cyclic movement
of material. The location of the spray nozzle at
the bottom of the fluidized bed of particles is
what sets our Wurster process apart from
other coating methods. Differential air streams
move the bed of particulate upward in a cyclic
motion inside the chamber as it is coated with
an atomized material to create a core-shell
structure. This configuration insures that the
coating material can be applied efficiently to
individual particles while controlling for
agglomeration. The process can be continued
until the desired uniform film thickness is
achieved through depositing one or many
unique layers to the core.
24. FLUID-BED COATING CONT..
➢ A coating is applied onto powder particles in a batch process or a continuous
setup
➢ The powder particles are suspended by an air stream at a specific temperature and
sprayed with an atomized, coating material
➢ 5–50% of coating is applied, depending on the particle size of the core material and
application of the encapsulate
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25. FLUID-BED COATING CONT..
➢ The particles to be coated by fluid bed should ideally be spherical and
dense, and should have a narrow particle size distribution and good
flowability
➢ Spherical particles have the lowest possible surface area and require less
coating material for the same shell thickness than nonspherical ones
➢ Sharp edges could damage the coating during handling
➢ Fine and low-dense particles might face the risk of accumulating on the filter
bags in the top of the machine
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26. EXTRUSION
Extruders consist of four distinct parts:
1)An opening though which material enters the barrel, that may have a hopper that is
filled with the material(s) to be extruded, or that may be continuously supplied to in a
controlled manner by one or more external feeder(s),
2)A conveying section (process section), which comprises the barrel and the
screw(s) that transport, and where applicable, mix the material,
3)An orifice (die) for shaping the material as it leaves the extruder,
4)Downstream auxiliary equipment for cooling, cutting and/or collecting the finished
product.
Flavours can be added through pump to encapsulant material.
27. EXTRUSION CONT..
➢ Exclusively for the encapsulation of volatile and unstable flavors in glassy
carbohydrate matrices
➢ This process is the very long shelf life imparted to normally oxidation-prone
flavour compounds, such as citrus oils, because atmosphere gases diffuse very
slowly through the hydrophilic glassy matrix, thus providing an almost
impermeable barrier against oxygen.
➢ Carbohydrate matrices in the glassy states have very good barrier properties
and extrusion is a convenient process enabling the encapsulation of flavours in
such matrices
➢ Allows the encapsulation of heat-sensitive material, such as Lactobacillus
acidophilus, which cannot be achieved in a typical carbohydrate matrix
because of the much higher processing temperatures typically used.
➢ The very low water content in the extruding mass prevents the degradation
of the enzyme even at high temperatures for short periods of time. 27
28. MELT EXTRUSION AND MELT
INJECTION
➢ Carbohydrate materials can be mixed with an active when molten, at a
temperature above 100°C
➢ Pressed through one or more orifices (extrusion)
➢ Finally quenched to form a glass in which active agent have relatively little
mobility
➢ Two processes to encapsulate active agent in a carbohydrate melt can be
distinguished.
One is melt injection, in which the melt (composed of sucrose,
maltodextrin, glucose syrup, polyols, and/or other mono- and
disaccharides) is pressed through one or more orifices (filter) and then
quenched by a cold, dehydrating solvent. This is a vertical, screwless
extrusion process.
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29. MELT EXTRUSION AND MELT
INJECTION CONT..
➢ Isopropanol, and also liquid nitrogen, is used as the dehydrating solvent.
The coating material hardens on contact with the dehydrating solvent, thereby
encapsulating the active.
➢ The size of the extruded strands is reduced to the appropriate dimensions
inside the cold solvent during vigorous stirring, thereby breaking up the
extrudates into small pieces.
➢ Any residues of active agent on the outside will be washed away by the
dehydrating solvent.
➢ Encapsulates made by melt injection are water-soluble and have particle sizes
from 200 to 2,000 μm
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30. MELT EXTRUSION AND MELT
INJECTION CONT..
➢ Using an extruder with one or more screws in a continuous process.
➢ Very similar to melt injection
➢ The main differences: melt extrusion utilizes screws in a horizontal position
and that the extrudates are not surface washed.
➢ Extruders are thermomechanical mixers that consist of one or more screws in
a barrel. Most often, double screw extruders are preferred
➢ Extrudates can be composed of starch, maltodextrins, modified starches,
sugars, cellulose ethers (like hydroxypropyl cellulose or hydroxypropyl methyl
cellulose), proteins, emulsifiers, lipids, and/or gums.
➢ Melt extrudates for use in food products are composed of “thermoplastic”
starch.
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33. OILS AND FATS
Long chain omega-3 fatty acids reduce the risk of heart disease, inflammatory and
immune disorders and have a role in early development.
Epa (eicospentaenoic acid) and dha (docosahexaenoic acid) levels in milk can be
increased by incorporation of fish oils.
Incorporation of fish oils into food formulations have limited success mainly due
to fishy flavors coming through in the consumer products.
Microencapsulation extends the shelf life of fish oils in powder form
increasing its versatility as a nutritional ingredient in food formulations.
Fish oil powder successfully incorporated into a number of food products,
including infant formulae at levels to satisfy the recommended daily intake
of omega-3 polyunsaturated acids.
34. VITAMINS
Many vitamins are relatively unstable and their ability to
maintain activity in foods depends on pH and reactions to
heat, light, oxygen and enzymes.
Lipid soluble vitamins such as vitamin A, beta carotene
and vitamins D, E, K are much easier to encapsulate then
water soluble ingredients.
When cheese milk is fortified with vitamin D entrapped in
liposome higher levels of vitamin D were found in cheese
curd.
35. MINERALS
Undesirable interactions between unprotected mineral salts
and components in milk can lead to precipitation, color and
flavor problems.
Encapsulating calcium salt in a lecithin liposome it was
possible to fortify 100g soya milk with up to 110mg calcium.
The soya milk remained stable at 4 degree C for at least one
week.
Microencapsulated iron ingredients can prevent off flavor
development and maintain bioavailability.
36. PROBIOTIC BACTERIA
A probiotic is a “live microbial supplement which beneficially effects the
host by improving its intestinal microbial balance.”
Microencapsulation of probiotic bacteria can improve its survival during
storage.
Probiotic bacterial cells encapsulated in calcium alginate provided
protection in fermented frozen dairy desserts.
Survived at low pH of fermented product and in acidic conditions
encountered in human stomach and could be delivered in the intestine.
37. FLAVOR ENCAPSULATION
Flavors consist of tens to hundreds of aromatic, volatile
organic compounds.
Microencapsulation can protect flavors, it can extend shelf life
and stability, control flavor release and provide liquid flavors.
The objectionable tastes and aroma of popular nutritional
ingredients like soy extracts, bitter herbs and omega-3 oils,
can be masked by microencapsulation.
Microencapsulation can be used to help to increase the
particle size of a flavor ingredient.
38. ENZYMES
Microencapsulation of beta galactosidase in liposomes can be used to act in vivo but
protect from acting on lactose during storage.
Emulsifiers can be used as effective coating material to microencapsulate lactase.
Liposomes containing enzymes reduce the ripening time by 30-50% as well as improve
texture and flavor.
ANTIOXIDANTS
40. FUNCTIONS OF CONTROLLED RELEASE IN FOODS
A substance in formulated food released upon
consumption but prevented from diffusion during the
series of operations in food processing.
A substance is released in a specific processing step, but
protected in preceding steps.
Immunoglobulins have potential in functional food
development as they afford protection against GIT
infection.
41. CONCLUSION
Microencapsulation offers
alternative methods for the
development of functional dairy
products. Its suitability depends
on the product, the need for
protection of food components
and timed release of
nutraceuticals. It can provide
novel solutions to problems
encountered in the development
of healthy properties of foods.
42. FUTURE TRENDS
New microencapsulation techniques are devised and
invented by academics and researchers.
It offers alternate method for the development of
functional dairy food.
Near about 1000 and above patents were filed
concerning various microencapsulation processes and
their applications and over 300 of these patents were
directly related to food ingredient encapsulation.
