Microencapsulation for Development of Functional Dairy Food

By: Solanki Manoj

Department of Dairy Chemistry, N.D.R.I.,Karnal

MICROENCAPSULATION

• It is defined as a technology of packaging solids, liquids or gaseous materials in miniature, sealed capsules that can release their contents at controlled rates under the influences of specific conditions.

Active ingredient > Process > coated particleActive ingredient > Process > coated particle

Terms Related To Encapsulation

Suspending liquid

Core material

Dehydrationmedia

Wall/capsule

TERMS

WHY ENCAPSULATE???????

CREATE NEWCREATE NEWFUNTIONAL FUNTIONAL

FOODFOOD

ENHANCEDENHANCED ACCEPTABILITYACCEPTABILITY

CONTROLLEDCONTROLLEDRELEASERELEASE

IMMOBILIZEIMMOBILIZE

PROTECTIONPROTECTION

WHYWHYENCAPSULATEENCAPSULATE

Properties of Ideal Coating Material

Good rheological properties at high concentration and easy for manipulation during the process of encapsulation.

Ability to disperse or emulsify the active material and stabilize the emulsion produced.

Non-reactivity with the material to be encapsulated both during processing and on prolonged storage.

Ability to seal and hold the active material within its structure during processing or in storage.

Complete release of the solvent or other materials that are used during the process of encapsulation, under desolvenization conditions.

Ability to provide maximum protection to the active material

against environmental conditions (e.g., heat, light, humidity).

Solubility in solvents acceptable in the food industry, e.g., water,

ethanol, etc.

Ability to meet specified or desired capsule solubility properties

and active material release properties.

Economy of food-grade substance.

Approved by controlling authority.

Methods of Encapsulation

Coacervation

Co-crystalization

Molecular inclusion

Spray drying

Spray cooling/chilling

Extrusion

Fluidized Bed

Melt injection

Liposome

CoacervationCoacervation microencapsulation is the phase separation of one or many hydrocolloids from 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.

Coacervation is a unique 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.

Coacervation is typically used to encapsulate flavour oil and can also be adapted for the encapsulation of fish oils, nutrients, vitamins, preservatives and enzymes.

Coacervation Formation

Co-CrystallizationSyrup blend

Concentration

Supersaturated solution

Transformation or crystallization

Microsized crystallization(incorporated product)

Agglomeration

Drying milling and screening

Functionally crystallized product

Flavour material

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 cylclodextrin is torus shaped, where core material can fit and released after heat treatment

β cylclodextrin

Spray DryingSpray Drying is the most commonly used encapsulation method in the food industry.

The process is economical and flexible uses equipment that is readily available, and produces particles of good quality.

The process involves three basic steps:

Preparation of a dispersion or emulsion to be processed

Homogenization of the dispersion and

Atomization of the mass into the drying chamber.

Spray dried ingredients typically have a very small particle size (generally less than 100µm) which makes them highly soluble.

Spray drying contd….

Typical shell materials include gum acacia, maltodextrins, hydrophobically modified starch and mixtures. Other polysaccharides like alginate, carboxymethylcellulose and guar gum.

Proteins like whey proteins, soy proteins, sodium caseinate can be used as the wall material in spray drying.

Multistage Spray Dryer

Spray cooling/chilling is the least expensive encapsulation technology.

It is used for the encapsulation of organic and inorganic salts, textural ingredients, enzymes, flavors and other functional ingredients.

It improves heat stability, delay release in wet environments, and/or convert liquid hydrophilic ingredient into free flowing powders.

Spray cooling/chilling is typically referred to as ‘matrix’ encapsulation because the particles are more adequately described as aggregates of active ingredient particles buried in the fat matrix.

Spray Cooling/ Chilling

A spray cooled particle. The red arrows point to active ingredient crystals sticking out of the fat matrix.

Spray Cooler Two-Stage, Counter current

Melt Extrusion

In melt-extrusion process forcing the core material, which is dispersed in a melt carbohydrate carriers through a series of die to form sheets, ropes or threads of different dimensions.

Encapsulant ingredients like flavours can be added either at the feed port of the extruder or to the molten mass in the final zone using specialized pump systems.

The particular advantage of the melt-extrusion glass encapsulated products is the ability to supply larger flavour particles for visual impact in products.

Larger flavour particles will dissolve slowly and exhibit some protection, controlled-release properties.

Melt extrusion flow diagram

1

23 5

8 9

11

7

4

6

10

12

1. Motor drive

2. Solids Feed

3. Water

4. Water pump

5. Flavour

6. Flavour pump

7. Co-rotating screws

8. Heating Jacket

9. Transition zone

10.Die

11.Take off conveyor

12.Cooling air

Fluidized BedFluidized bed technology is a very efficient way to apply a uniform layer of shell materials onto solid particles.

It is one of the few technologies capable of coating particles with different kinds of shell material like polysaccharides, proteins, emulsifiers, fats, complex formulations, powder coatings, yeast cell extract etc.

A number of food ingredients can be encapsulated by fluidized bed coating such as ascorbic acid, acidulants for processed meat and leavening agents.

Typical fluidized bed system can efficiently process particles from 100µm to a few millimeters.

The Wruster Process

This technology is characterized by the location of a spray nozzle at the bottom of a fluidized bed of solid particles.

The particles are suspended in the fluidizing air stream that is designed to induce a cyclic flow of the particles past the spray nozzle.

The nozzle sprays an atomized flow of coating solution, suspension, or other coating vehicle.

The technology can be used to encapsulate solid materials with diameters ranging from near 50µm to several centimeters.

Wruster Process can be used to encapsulate vitamins, minerals, and functional food ingredients.

Melt injectionThis process is often referred to as the “Durarome” process after the product trade name.

In this method sugar syrup or sugar-corn syrup is made.

Ingredients like flavour oils are then added to the hot molten sugar, the pressure vessel is closed and high shear mixing is employed to emulsify the flavour oil.

The hot sugar emulsion is expelled through fine orifices into the chilled solvent bath (Isopropanol).

The product is obtained as fine threads free of surface oil.

The property is especially important when citrus oils are to be encapsulated.

Liposome Microencapsulation

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.

Liposomes are usually made of phosphatidylcholine (lipid) molecules although mixtures of phospholipids can also be employed to make liposomes.

A unique property of liposomes is the targeted delivery of their content in specific parts of the food stuffs.

Liposomes can also be used to deliver the encapsulated ingredient at a specific and well-defined temperature.

Simplified representation of molecular organization of a liposome microcapsule in water

VETERINARY

CHEMICAL INDUSTRY

PHOTO-GRAPHY

ELECT-RONICS

WASTE TREATMENT FEED

AGRI-CULTURE

TEXTILE

BIOTECH

MEDICINE

FOOD

APPLICATIONS

Trends in Microencapsulation Technologies

Opportunities for Dairy Functional Food

Oils and FatsFish Oils

Long chain Omega-3 fatty acids reduce the risk of heart disease, inflammatory and immune disorders and have a role in early development.

Eicospentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in milk can be increased by incorporation of fish oils.

Incorporation of fish oil into food formulations have had limited success mainly because of fishy flavours coming through in the consumer products.

Fish oils contd.

Microencapsulation extends the shelf-life of fish oil in powder form increasing its versatility as a nutritional ingredient in food formulations.

Fish oil powder produced by microencapsulating fish oil with micellar casein in the form of SMP using homogenisation and spray drying had acceptable taste and modest shelf-life of 31 weeks at 4ºC.

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.

VitaminsMany of the vitamins are relatively unstable and their ability to maintain activity in foods depends on pH and reactions to heat, light, oxygen, oxidizing agents and enzymes.

Lipid soluble vitamins such as vitamin A, -carotene and vitamins D, E, K are much easier to encapsulate then water soluble ingredients.

Using microencapsulated vitamins in dairy products reduces loss during storage.

When cheese milk is fortified with vitamin D entrapped in liposome higher levels of vitamin D were found in cheese curd.

Vitamin losses and typical overages added to compensate for losses during processing and

storage

Vitamin Product % Overages recommended

-Carotene BeveragesDairy Products

25-4025

Vitamin C BeveragesDairy Products

40-20050

Vitamin E BeveragesDairy Products

10-255

Vitamin A Spray dried skim milk

10-25

Vitamin D Spray dried skim milk

10-25

MineralsUndesirable interactions between unprotected mineral salts and components in milk can lead to precipitation, colour and flavour problems.

Encapsulating calcium salt (calcium lactate) in a lecithin liposome it was possible to fortify 100g soya milk with up to 110 mg Calcium. The soya milk remained stable at 4°C for at least 1 week.

Microencapsulated iron ingredients can prevent off flavour development and maintain bioavailability. Heat treatment and storage for 6 months did not result in decreased bioavailability of Fe-fortified milk. (Boccio et al. 1997)

Probiotic BacteriaA probiotic is a “live microbial supplement which beneficially affects the host by improving its intestinal microbial balance (Fuller, 1989).

Microencapsulation of probiotic bacteria can improve its survival during storage.

Probiotic bacterial cells encapsulated in calcium alginate provided protection in fermented frozen dairy desserts (Shah and Ravula, 2000).

Survived at low pH of the fermented product and in acidic conditions encountered in human stomach and could be delivered in the intestine.

Flavour EncapsulationFlavours consist of tens to hundreds of aromatic, volatile organic compounds.

Microencapsulation can protect flavours, it can extend shelf life and stability, control flavour release and provide liquid flavours with a granular form.

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 also be used to help to increase the particle size of a flavour ingredient.

Liposomes have the ability to carry fat-based flavours in their bilayer, as well as water soluble flavours in the core of the vesicle.

EnzymesMicroencapsulation of -glactosidase 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 (Kwak et al., 2001).

Liposomes containing enzymes reduce the ripening time by 30-50% as well as improve texture and flavour.

Antioxidants

Ascorbic acid by entrapping it in a liposome together with vitamin E is used for protection of emulsion-type foods (Reineccius, 1995).

Ascorbic acid with Vitamin E has synergistic antioxidant effect.

Controlled Release

Controlled release of encapsulated ingredient at the right place and the right time is gaining significance.

Improve effectiveness of food additives, broaden application range and ensure optimal dosage.

The balance between entrapment and delivery is determined by the selection and formulation of the coating material.

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 (e.g., flavours, nutrients).

A substance is released in a specific processing step, but protected in preceding steps (e.g., leavening agents).

Immunoglobulins have potential in functional food development as they afford protection against gastrointestinal infection.

Mechanism of Controlled Release of ingredients

Shefer and Shefer (2003)

ConclusionMicroencapsulation 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.

Future Trends

New microencapsulation technologies are devsed and invented by academics and researchers.

Microencapsulation 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.