Encapsulation Technologies Protect Key Ingredients

Encapsulation technologies protect key ingredients and deliver them at just the right moment.

By Kantha Shelke, Ingredients Editor

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As consumers increasingly turn to foods as sources of health, processors are trying to cram in as many healthful ingredients as possible. Unfortunately, vitamins, minerals and other nutritive ingredients are not known for their pleasant tastes. But precision microencapsulation technologies can mask the taste or color of nutrients, mitigate nutrient loss during processing and generally help processors create foods with added value.

Kraft Foods, Northfield, Ill., is exploring nutrient microencapsulation technologies through NanoteK, a consortium of researchers from 15 universities and government labs recently created to explore improvements for the food industry. "The widespread use of such technology is all but inevitable in the next few years," says Manuel Marquez-Sanchez, head of the consortium.

Encapsulation involves the incorporation of ingredients, enzymes, cells or other materials into small capsules for delivery of the contents at the appropriate time. By creating a barrier between reactive components, encapsulation protects oxygen-sensitive flavor and color compounds during processing and storage so consumers can enjoy the results at a later time and for a longer time. The process also protects these and other highly reactive materials from interacting with other ingredients to form non-nutritive complexes and compounds with undesirable color or flavor.

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.

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 history

Encapsulation 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 methods

Ingredients 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.

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 gum

How 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.

The creators of Jolt gum took on quite a challenge when they set out to create a good tasting, effective caffeine gum. Microencapsulation to the rescue!

Recently, advancing sophistication of encapsulation technologies has enabled the controlled release of critical ingredients and even the staged delivery of ingredients to create multi-dimensional sensations. Dentyne Ice Cool Frost claims to have alternating bursts of sweetness (aspartame), cooling sensation (polyols) and mint flavor.

Kevin Gass of Gum Runners LLC (www.joltgum.com), Hackensack, N.J., said he did not know how difficult it would be to create a good tasting, effective caffeine gum. The company employed microencapsulation to deliver good taste and effective caffeine release in Jolt Caffeine Energy Gum. Two pieces of this gum provide the caffeine boost of a cup of coffee; one piece is equal to a cola.

Chicago-based O'lala Foods Inc. (www.olalafoods.com) used microencapsulation to create Choco'la -- a sugar-free and fat-free chewing gum that’s a chocolate alternative for diabetics and people on weight management programs. "O'lala's patent pending RST flavor system helps make low-fat products with the creamier mouthfeel associated with higher fat products,” explains Nik Rokop, nanotechnology expert and advisor to O'lala Foods.

“Microencapsulation technologies helped create fat mimetics that impart a creamy taste without all of the fat. Choco'la has creamy chocolate taste because we infused microencapsulates of real cocoa into a premium gum base," Rokop continues. “We also microencapsulated cocoa powder to get rid of the gritty texture and to create Chocolate On-the-Go -- a heat-stable chocolate that would not melt in your pocket or purse,” adds CEO Neil Wyant.

Hiding fish oils in bread

Omega-3 fatty acids are considered essential because they are needed throughout the human life cycle, cannot be produced in the human body and therefore must be added through the diet. Two principal omega-3s are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – long-chain polyunsaturated fatty acids that are biologically active and physiologically essential for human health.

Americans do not consume enough EPA and DHA, perhaps because they are found in fish and fish oil and fish does not rank high in the American diet. What if you could get them in baked goods and other products without the taste and smell associated with fish oils?

Ocean Nutrition Canada Ltd. (www.ocean-nutrition.com), Dartmouth, Nova Scotia, employed microencapsulation to create Meg-3, a powder rich in EPA, DHA and omega-3s. This fortification can be added to a number of foods, including baked products, dairy products, cereal and nutrition bars, beverages (malts, shakes and smoothies) salad dressings and sauces, soups and meats. Three U.S. bread manufacturers have added Meg-3 to products: a white bread from New York-based Wegmans Food Markets; whole-grain bread from The Baker, Milford, N.J.; and Smart & Healthy 100 percent whole wheat bread from Arnold Foods Co., Long Island, N.Y.

Thanks to microencapsulation, Ocean Nutrition's Meg-3 can be used to fortify bread with no fishy aroma or taste.
“Freshly processed fish oil, like freshly made, high-quality sushi, is not fishy in odor or taste; the fishy notes that consumers associate with fish result only when fish oil has oxidized and become rancid,” explains Jennifer Berry, Ocean Nutrition’s director of business development-healthy ingredients. "Microencapsulation completely surrounds the active ingredient and leaves only traces on the surface of the encapsulated material. Less exposed material means less susceptibility to oxidation and less development of rancidity, off-flavors and aromas.

“Cross-linked gelatin produces a strong shell with superior integrity but sufficient flexibility so as to withstand shear and the temperature extremes associated with bakeries and dairy-based beverage production facilities,” she continues. “The beaded material, finer than flour, blends easily with flour and dairy ingredients and delivers the active contents only when acted upon by gastric proteases in the gastrointestinal tract."

A combination of encapsulation technologies – microencapsulation and coacervation – helped Beth Vincent, public health expert and mother of three, pack DHA as well as 14 vitamins and minerals recommended by the National Academy of Sciences into the Oh Mama! nutrition bar. She co-founded Vincent Foods (www.ohmamabar.com) in Baltimore, Md., to create these tasty, low-fat, healthy bars formulated specially for women who are trying to conceive, who are pregnant or who are nursing.

The Oh! Mama bar also provides 100 percent of the daily iron requirement in a palatable and bioavailable form – a remarkable formulation feat.

Minerals, unlike vitamins, are coated not so much as to protect them from the environment as to protect the rest of the formulation from them. Iron, for example, can trigger the oxidation of fats and oils in infant formulas and reduce the bioavailability of both the oils and the mineral. Copper has been known to cause an undesirable blue color in foods, while calcium tends to create gritty texture and chalky taste.

Biodar microencapsulation technology from PL Thomas overcomes these taste and texture issues, so processors – often limited to adding small amounts of minerals – can add up to 100 percent of the daily requirement of iron, calcium, chromium, copper, magnesium, manganese, potassium and zinc.

Encapsulation allows for delaying the action of sodium bicarbonate in foods such as Red Baron's Bake To Rise pizza, manufactured by Schwan's Consumer Brands, Bloomington, Minn. Cameron, Wis.-based Primera Foods (www.primerafoods.com) created the PrimeCap Bakery Blend line of encapsulated leavening systems so a balanced blend of sodium bicarbonate and phosphate is release only when desired -- in the oven or microwave -- to create the increased volume and textural characteristics desired by consumers.

Microencapsulation also is being used by Maxx Performance (www.maxxperform.com), Chester, N.Y., to deliver phytonutrients including sulbutiamine – a nootropic or cognitive enhancement compound gaining prominence in the dietary supplement arena – pure resveratrol for cardiovascular health and glucaric acid with potential anti-cancer properties. According to CEO Winston Samuels, microencapsulation is merging novel technologies with traditional food processing to create foods that can enhance performance.

Even newer technologies

There are even more encapsulation technologies in the pipeline. BASF (www.basf.com), Florham Park, N.J., adds several layers of natural material to coat microspheres of ingredients to create Cavis Microcaps.

Just as a teabag retains the tea leaves but allows in water, Cavis Microcaps contain yeast but allow sugar to be transported through the membrane to allow fermentation to occur inside the multilayer capsule. Made from algae, silica, calcium and oil, the capsules are suitable for encapsulation of vitamins, minerals, probiotics and fatty acids and are a very gentle encapsulation process.

Cavis Microcaps with yeast are used to make sparkling wine. Carbon dioxide and alcohol produced inside the Microcaps can exit into the wine without the risk of yeast turning the wine turbid. They also can lower wine production costs because the yeast capsules are easier to separate from the wine than pure yeast.

NutraLease micrencapsulation technology from NutraLease Ltd. (www.nutralease.com) of Mishor, Adumin, Israel, delivers CoQ10 in nano-sized vehicles for beverages. The micro-emulsion technology uses micelles, which are self-assembled structured liquid particles with a diameter of 30 nanometers or less. These small particles readily penetrate cell membranes and dramatically increase the bioavailability of the phytonutrients they carry and protect.

"Encapsulation technology is advancing at an incredible rate," according to Ram Chaudhari, senior vice president-research and development at Fortitech, Inc., Schenectady, N.Y. "The number of fortified products these days has grown – from simple fortified flours of yesterday to complex solutions and even tube feeding."



Kantha Shelke is a principal at Corvus Blue LLC, a Chicago firm that specializes in competitive intelligence and expert witness services. Contact her at kantha@ais.net or 312-951-5810.
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