Thanks to two techniques — coacervation and microencapsulation — the Oh! Mama provides 100 percent of a pregnant woman's daily iron requirement, plus DHA and 14 vitamins and minerals.
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Encapsulation protects nutrients such as iron and vitamin C through processing and storage until the foods are consumed. It turns fragile, volatile and easy-to-spoil liquid ingredients that require controlled storage conditions into stable, easy-flowing powdered solids that can survive the rigors of processing and packaging and be viable even with ambient storage. Conversion of liquids into solid powders also helps simplify processing, often by converting batch production into continuous manufacturing.The market for encapsulated ingredients could be huge, based on market research estimates. The Freedonia Group (
www.freedoniagroup.com), Cleveland, predicts the market for functional foods containing medically beneficial nutrients will exceed $40 billion in 2008.
Chemical Market Reporter estimates the demand for encapsulation technologies is growing at around 10 percent annually, driven both by increasing fortification with health ingredients and consumer demand for novel products.
A capsule historyEncapsulation technology, developed three decades ago, largely involves enveloping or entrapping a liquid, solid or sometimes even a gas -- which may be called the core material, internal phase, actives, fill or payload -- in an enclosing material commonly referred to as the carrier, shell, wall, capsule or membrane.Entrapment in the early days entailed impermeable materials and relied on mechanical means to crush and deliver the contained ingredients for flavor, aroma, leavening ... or enzymatic activity, as in the case of pectin esterase for juice clarification, rennet for milk coagulation or invertase for sucrose inversion.The commercial production of yogurt, for example, was brought about by the encapsulation and immobilization of lactic acid bacteria (lactobacillus lactis) so they could survive pasteurization but take part in fermentation. Now, even more sophisticated techniques in DanActive from Dannon also protect these beneficial bacteria from degradation in the stomach so they can provide probiotic effects in the lower intestine.The coating may be made from sugars, proteins, gums, natural and modified polysaccharides, synthetic polymers and even fats -- whatever it takes to protect the core material from the environment, moisture and heat. Encapsulated materials can range from 0.5 to 250 microns in diameter; the particle size and the size distribution may be easily adjusted to the application. A wide distribution range allows for delivery of the core materials over a prolonged period, and a narrow range allows for more rapid and precise delivery.The core materials typically are released from a microcapsule one of four ways: mechanical capsule rupture, capsule wall dissolution, capsule wall melting or diffusion through the wall.For a long while, encapsulation was regarded as expensive and too specific for the food industry. In the past decade, cost-effective preparation and increased production volumes contributed to the affordability of encapsulated ingredients, making them increasingly valuable to food processors.
Encapsulation methodsIngredients may be encapsulated by various physical and chemical techniques including: spray drying, spray cooling, extrusion coating, fluidized bed coating, inclusion complexation, lipid entrapment, coacervation and centrifugal extrusion.Elements essential and common to all methods are:
- Coating around the material to contain it with integrity.
- Ensuring protection from undesirable conditions.
- Delivering it unchanged at the appropriate stage.
- Understanding the basics and suitability of the method to the food product application is essential to developing products that deliver what they promise.
Spray drying is probably the most economical and most widely used method, especially for flavors. Solutions of carrier materials such as modified starch, maltodextrin or gums are homogenized with the core material and atomized; the hot air evaporates the solvent and the carrier dries entrapping volatile material. This technique is particularly useful for heat-labile flavors, but the disadvantage is the resulting encapsulated material needs to be agglomerated to render it soluble. Thus a mixture of citral and gum arabic may be subjected to high air velocity at 300-400°C to effectively entrap the lemon flavor without degradation.Spray cooling typically is used for vitamins, acidulants and minerals such as ferrous sulfate. It's often employed to encapsulate materials that are liquid, heat-sensitive and insoluble in common solvents, so they may be released when the wall material is melted. For example, gluconodeltalactone, lactic and citric acids -- used to enhance the flavors of cured meats such as pepperoni, hard salami and summer sausages -- are encapsulated to prevent them from reacting with the foods. The alternative is to rely on fermentation -- a time consuming, difficult to control and expensive proposition.
NOTE TO PLANT OPS
No single encapsulation technique can produce the complete range of products desired by potential users. Ensure that the encapsulated ingredient is appropriate not only for the particular food product application, but also for your process and plant conditions.
First, determine the purpose for the encapsulation, whether it is to change the form of the ingredient from a liquid state to a solid state, provide controlled release, improve stability, improve flowability, reduce dusting or separate incompatible ingredients.
Next, review ingredient specifications to ensure the particle size and flow characteristics are in alignment with your process and facility schematics.
You may be pleased to learn encapsulation has allowed you to store and handle at ambient temperatures ingredients that formerly were sensitive. If the process also has changed liquid ingredients into powdered ones that may simplify or speed up processing.
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Extrusion coating is effective for isolating the core material from the outside and is used to produce encapsulated vitamin C, colors or flavors that can last up to two years in dry food applications. End-product examples include Tang drink mix and Jello gelatin.Fluidized bed coating is used for hot-melt coatings such as stearines, fatty acids and waxes, which solidify in cool air and release the core upon heating or shear. The process also may be used with maltodextrins, gums and starches, which form the shell when hot air evaporates the solvent. Fluidized bed encapsulation is particularly effective for separating acids such as ascorbic, lactic and vitamin C from other ingredients in fortified foods and for preserving materials such as sodium bicarbonate in baked goods.In the inclusion complexation technique, cyclodextrins -- cyclic (-1,4) -linked oligosaccharides of -D-gluco-pyranose – are used to increase the aqueous solubility of oily materials by entrapping them in their hydrophobic center at high temperatures (200°C or more). The resulting complex is relatively stable, and the hydrophilic outer surface facilitates suspension in water. The entrapped materials are generally odorless and the highly aromatic contents such as onion and garlic oils are released in the moisture and temperature conditions of the mouth.Lipid entrapment creates liposomes – initially for the medical industry and now popular with food processors – to efficiently encapsulate sensitive ingredients such as enzyme and flavor molecules under mild conditions and avoiding high temperatures or oxygenation. Sears Laboratories (
www.drsears.com) – connected with world-famous medical researcher and diet book author Dr. Barry Sears -- of Marblehead, Mass., has created liposomes with greater stability allowing for incorporation of higher levels of water-insoluble ingredients, especially those prone to oxidation. Lipid entrapment is a key in the production of nutrient-rich foods such as SmartZone (
www.hershey.com) and Oh! Mama (
www.ohmamabar.com) nutrition bars. For emulsions such as spreads and margarines, liposomes can help prevent oxidation of the unsaturated fats that have replaced the more stable saturated fats. Natural antioxidants such as vitamin C entrapped in liposomes with alpha-tocopherol (vitamin E) in the outer layer are a natural and healthier alternative to the lipid-soluble, chemical derivatives of vitamin C.Coacervation is an expensive but efficient way to incorporate nutritionally important and health-promoting compounds into processed foods without reducing their bioavailabilty and without affecting the taste of the food itself. Bioavailability -– the degree and rate at which substances are actually absorbed by the body -- is a key issue hounding manufacturers of functional foods, according to Rodger Jonas, national business development manager at PL Thomas (
www.plthomas.com), Morristown, N.J.Rotational or centrifugal suspension separation is a relatively new technique used to protect ingredients, such as aspartame, vitamins or methionine, that are sensitive to or readily absorb moisture. A resulting product is AsparCote from Biodar (
www.biodar.com), an American-Israeli joint venture and a subsidiary of LycoRed. It’s an aspartame product that can be added to dairy products before pasteurization. According to Jonas, a heat-stable aspartame presents a huge opportunity for makers of dietetic dairy-based beverages. It is important to understand the method releasing the ingredients to help select the appropriate matrix or membrane. It helps also to take into consideration the chemical nature, morphology and glass transition temperature of the shell – attributes that can influence stability and diffusion of the core materials.
Longer-lasting chewing gumHow long the flavor lasts is a big consideration when consumers reach for chewing gum. Encapsulation technologies are playing several roles in improving the taste of gums.The cooling sensation of menthol or the heating sensation of cinnamaldehydes is subjected to an initial spray-drying step to create the smallest particle size possible -- down to 0.5 micron. Those particles then are coated with a gum, wax or other water-insoluble substance so that with each chew, one or two capsules burst to provide the intended sensation.