Hidden ingredients take cover in a capsule

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.