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 particle
Terms Related To Encapsulation Wall/ capsuleSuspending Dehydration liquid TERMS media Core material
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 materialagainst 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 propertiesand active material release properties.Economy of food-grade substance.Approved by controlling authority.
Coacervation• Coacervation 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.
Co-Crystallization Syrup blend Flavour material Concentration Supersaturated solution Transformation or crystallization Microsized crystallization (incorporated product) Agglomeration Drying milling and screening Functionally crystallized product
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 usedencapsulation method in the food industry.The process is economical and flexible usesequipment that is readily available, and producesparticles 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 smallparticle size (generally less than 100µm) which makesthem highly soluble.
Spray drying contd….Typical shell materials include gum acacia,maltodextrins, hydrophobically modified starchand mixtures. Other polysaccharides likealginate, carboxymethylcellulose and guar gum.Proteins like whey proteins, soy proteins, sodiumcaseinate can be used as the wall material inspray drying.
Spray Cooling/ ChillingSpray cooling/chilling is the least expensive encapsulationtechnology.It is used for the encapsulation of organic and inorganic salts,textural ingredients, enzymes, flavors and other functionalingredients.It improves heat stability, delay release in wet environments,and/or convert liquid hydrophilic ingredient into free flowingpowders.Spray cooling/chilling is typically referred to as ‘matrix’encapsulation because the particles are more adequatelydescribed as aggregates of active ingredient particles buried inthe fat matrix.
A spray cooled particle. The red arrows point to active ingredient crystals sticking out of the fat matrix.
Melt ExtrusionIn melt-extrusion process forcing the core material,which is dispersed in a melt carbohydrate carriersthrough a series of die to form sheets, ropes or threadsof different dimensions.Encapsulant ingredients like flavours can be addedeither at the feed port of the extruder or to the moltenmass in the final zone using specialized pump systems.The particular advantage of the melt-extrusion glassencapsulated products is the ability to supply largerflavour particles for visual impact in products.Larger flavour particles will dissolve slowly and exhibitsome protection, controlled-release properties.
Melt extrusion flow diagram 1. Motor drive 1. Co-rotating screws 3 5 2. Solids Feed 2. Heating Jacket2 3. Water 3. Transition zone 4 4. Water pump 4. Die 5. Flavour 5. Take off conveyor 6 6. Flavour 6. Cooling air pump 8 9 10 121 7 11
Fluidized BedFluidized bed technology is a very efficient way to apply auniform layer of shell materials onto solid particles.It is one of the few technologies capable of coating particleswith different kinds of shell material like polysaccharides,proteins, emulsifiers, fats, complex formulations, powdercoatings, yeast cell extract etc.A number of food ingredients can be encapsulated by fluidizedbed coating such as ascorbic acid, acidulants for processedmeat and leavening agents.Typical fluidized bed system can efficiently process particlesfrom 100µm to a few millimeters.
The Wruster ProcessThis technology is characterized by thelocation of a spray nozzle at the bottom ofa fluidized bed of solid particles.The particles are suspended in thefluidizing air stream that is designed toinduce a cyclic flow of the particles past thespray nozzle.The nozzle sprays an atomized flow ofcoating solution, suspension, or othercoating vehicle.The technology can be used to encapsulatesolid materials with diameters ranging fromnear 50µm to several centimeters.Wruster Process can be used to encapsulatevitamins, minerals, and functional foodingredients.
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 hotmolten sugar, the pressure vessel is closed and highshear mixing is employed to emulsify the flavour oil.The hot sugar emulsion is expelled through fine orificesinto the chilled solvent bath (Isopropanol).The product is obtained as fine threads free of surfaceoil.The property is especially important when citrus oils areto 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
FOOD VE TE RINARY ME DICINE CH E M I CA L B I OT E CH I ND UST R Y APPLICATIONSP H OT O- TE XTI L EGR A P H Y E L E CT - A GR I - R ONI CS CUL T UR E W A STE T R E A T M E NT FEED
Oils and Fats Fish OilsLong chain Omega-3 fatty acids reduce the riskof heart disease, inflammatory and immunedisorders and have a role in early development.Eicospentaenoic acid (EPA) anddocosahexaenoic acid (DHA) levels in milk canbe increased by incorporation of fish oils.Incorporation of fish oil into food formulationshave had limited success mainly because offishy flavours coming through in the consumerproducts.
Fish oils contd.Microencapsulation extends the shelf-life of fish oil inpowder form increasing its versatility as a nutritionalingredient in food formulations.Fish oil powder produced by microencapsulating fish oilwith micellar casein in the form of SMP usinghomogenisation and spray drying had acceptable tasteand modest shelf-life of 31 weeks at 4ºC.Fish oil powder successfully incorporated into a numberof food products, including infant formulae, at levels tosatisfy the recommended daily intake of omega-3polyunsaturated acids.
Vitamins• Many 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, β-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 tocompensate for losses during processing and storage Vitamin Product % Overages recommendedβ-Carotene Beverages 25-40 Dairy Products 25Vitamin C Beverages 40-200 Dairy Products 50Vitamin E Beverages 10-25 Dairy Products 5Vitamin A Spray dried skim 10-25 milkVitamin D Spray dried skim 10-25 milk
Minerals• Undesirable 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 whichbeneficially affects the host by improving itsintestinal microbial balance (Fuller, 1989).Microencapsulation of probiotic bacteria canimprove its survival during storage.Probiotic bacterial cells encapsulated in calciumalginate provided protection in fermented frozendairy desserts (Shah and Ravula, 2000).Survived at low pH of the fermented product andin acidic conditions encountered in humanstomach and could be delivered in the intestine.
Flavour EncapsulationFlavours consist of tens to hundreds of aromatic, volatileorganic compounds.Microencapsulation can protect flavours, it can extendshelf life and stability, control flavour release and provideliquid flavours with a granular form.The objectionable tastes and aroma of popular nutritionalingredients like soy extracts, bitter herbs and omega-3oils, can be masked by microencapsulation.Microencapsulation can also be used to help to increasethe particle size of a flavour ingredient.Liposomes have the ability to carry fat-based flavours intheir bilayer, as well as water soluble flavours in the coreof the vesicle.
Enzymes• Microencapsulation of β-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.
AntioxidantsAscorbic acid by entrapping it in aliposome together with vitamin E is usedfor protection of emulsion-type foods(Reineccius, 1995).Ascorbic acid with Vitamin E hassynergistic antioxidant effect.
Controlled ReleaseControlled release of encapsulated ingredient atthe right place and the right time is gainingsignificance.Improve effectiveness of food additives,broaden application range and ensure optimaldosage.The balance between entrapment and deliveryis determined by the selection and formulationof the coating material.
Functions of controlled release in foodsA substance in formulated food released uponconsumption but prevented from diffusionduring the series of operations in foodprocessing (e.g., flavours, nutrients).A substance is released in a specific processingstep, but protected in preceding steps (e.g.,leavening agents).Immunoglobulins have potential in functionalfood development as they afford protectionagainst gastrointestinal infection.
Mechanism of Controlled Release of ingredients Shefer and Shefer (2003)
Conclusion Microencapsulation offersalternative methods for the developmentof functional dairy products. Itssuitability depends on the product, theneed for protection of food componentsand timed release of nutraceuticals. Itcan provide novel solutions to problemsencountered in the development ofhealthy properties of foods.
Future TrendsNew microencapsulation technologies are devsed andinvented by academics and researchers.Microencapsulation offers alternate method for thedevelopment of functional dairy food.Near about 1000 and above patents were filedconcerning various microencapsulation processes andtheir applications and over 300 of these patents weredirectly related to food ingredient encapsulation.