Consumers prefer food products that are tasty, healthy and convenient. Encapsulation is an important way to meet these demands by delivering food ingredients at the right time and right place. For example, encapsulates may allow flavor retention, mask bad tasting or bad smelling components, stabilize food ingredients and/or increase their bio availability. Encapsulation may also be used to immobilize cells or enzymes in the production of food materials or products, such as fermentation or metabolite production.

Encapsulation technology in food:
Encapsulation technology is applied in many industries, including food, medicines, fragrance and scratch-n-sniff products.

Within food technology, encapsulation is used to:
1. Act as a vehicle for the addition of yeast in brewing or lactic acid starter cultures in
dairy fermentation.
2. Enhance the appearance or flavor of food through natural and artificial flavors
And colors.
3. Fortify food products with additional nutrients, e.g. functional foods.
4. Aid preservation.
5. Ensure consistency.

Encapsulation involves the coating and entrapment of a pure material or mixture into another material. The coated or entrapped material is usually a liquid but can be a solid or gas. Natural examples include birds' egg shells, plant seeds, bacterial spores, skin and seashells.

Why encapsulate?
Encapsulation technology can:
1. Achieve a controlled release of a core material, e.g. sustained release of the core
Material over a period of time at a constant rate
2. Mask the taste of a capsule's core
3. Reduce the reactivity of core material, e.g. to oxygen and water
4. Ease the handling of the core, e.g. by prevent lumping, converting a liquid to a solid and
By being easy to mix
5. Dilute the core material, when used in small amounts, but achieve a uniform dispersion

How is the core materials released?
1. Core materials within capsules may be released through the shell by:
Mechanical compressive force
2. Dissolving in liquid (e.g. flavor capsules in a powder being diluted)
Melting during baking
3. Breaking and opening due to the shear in a blender
4. Diffusing at a slow rate due to water or temperature increase.

When designing encapsulation processes, it must be clearly established what type of functions encapsulated core can provide to the final product in order to select the most suitable coating material.

Coating material used:

Carbohydrates =Corn syrup, dextrin, starch, sucrose
Gum=Agar, gum Arabic, sodium alginate
Lipids= Beeswax, fat, oil, diglyceride, paraffin
Inorganic material=Calcium sulphate, clay, silicate
Cellulose= Ethyl cellulose, nitro cellulose
Protein=Albumin, casein, gelatin, gluten
Synthetic elastomer= Polyvinyl alcohol, polyvinyl acetate
Synthetic polymer= polybutadiene

Techniques for encapsulation:
• Spray drying
• Spray chilling
• Liposome entrapment
• Coacervation,
• Spray cooling
• Extrusion coating
• Inclusion complexation
• Centrifugal extrusion
• Fluidized bed coating
• Co-crystallization
• Rotational suspension separation
• Interfacial polymerization

Encapsulated ingredients and their application:
Microencapsulation can potentially offer numerous benefits to the materials being encapsulated. Various properties of active materials may be changed by encapsulation. For example, handling and flow properties can be improved by converting the liquid to solid encapsulated form. Hygroscopic materials can be protected from moisture and the stability of ingredients volatile or sensitive to heat, light, or oxidation can be protected, thereby extending their shelf lie. Materials that are otherwise incompatible can be mixed and used safely together.

Acidulants can be used in food for various reasons. They can be used as flavor modifiers, preservation aids, and processing aids. In addition they facilitate the textural effects in foods because of their interaction with other micro and macro molecules such as protein, starches, pectin and gums. And unencapsulated food acids can react with food ingredients to produce many undesirable effects. But encapsulated food acid can overcome this problem because they preclude oxidation and provide controlled release under such specific condition moreover encapsulated acids can reduce hygroscopisity, reduce dusting, and provide a high degree of flow-ability without clumping.
Encapsulated acids are used in meat processing industry to develop the color and flavor of the product. In baking industry stable acids are needed for controlled release of carbon dioxide during baking.

Flavoring agents:
The flavor industry depends heavily on encapsulation as a means of providing solid flavor compounds that offer them protection until consumption. Some of the commonly used encapsulated flavors are citrus oils, mint oils, onion and garlic oils, spice oleoresins, and whole spices
Encapsulation of sweeteners will reduce hygroscopisity and improve their flow-ability and prolongs their sweetness perception

Natural colors such s annatto, β-carotene, and turmeric present solubility during their use and may create dust clouds, encapsulated colors are easier to handle and offer improved solubility, stability to oxidation and control over stratification from dry blends.

One possible way to protect lipid moieties against oxidative deterioration is via encapsulation vitamins and minerals:
Most vitamins cannot be synthesized by the body and must be supplied by the diet. Encapsulation of vitamins and minerals offers many advantages as it reduces off-flavors contributed by certain vitamins and minerals, permits time release of the nutrient, enhances stability of vitamins to extremes in temperature and moisture, and reduces dusting when nutrients are added to dry mixes.

Encapsulation of enzymes could enhance their properties in number of very different ways. The complex biochemical structure of the enzyme can make it highly vulnerable to inactivation by other components or conditions within the food system. And by segregating it inside a microcapsule, it can be maintained in conditions that could otherwise be very harmful to it.

Encapsulation of viable bacterial cells has several advantages over encapsulation of isolated cheese ripening enzymes. The stability of enzymes in intact cells is greater than in extracts. Furthermore, production achieved by cells is easily manipulated by controlling substrate concentration in microcapsules.

Some hard candies can be made with entrapped carbon dioxide gas. The confections made with encapsulated carbon dioxide produce a sizzling effect on the tongue as the candy melts in the mouth.gas can also be injected into the encapsulation system and be coated together with the foaming and aromatic core mixtures. And other food additives can be encapsulated for various purposes.

Even though encapsulation technology has been extensively used by the pharmaceutical and chemical industry for many years, its application to food industry have lagged and stands great. Food ingredients are encapsulated for a variety of reasons including protection from volatization during storage, protection from undesirable interactions with other food components, minimization of flavor interactions or light-induced deteriorative reactions, and protection against oxidation.

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