Protecting Active Ingredients

By Donna Berry, Contributing Editor

One of the most-important factors in designing a functional food is maintaining product efficacy. For some ingredients, that requires an effort to protect them from the deleterious effects of processing and storage.

Multifaceted challenge

When working with multiple functional ingredients, the core challenge facing product developers is the complexity of the food matrix. A food product is comprised of many different ingredients that together form a complete, uniformly balanced physical and chemical nutritional system," says Ram Chaudhari, Ph.D., senior executive vice president and chief scientific officer, Fortitech Inc., Schenectady, NY. Many of these ingredients are multifunctional, so removing or adding new functional food ingredients may disrupt the total balance of the product. Undesirable interactions between the various components of complex foods and beverages increase the risk of quality deterioration in a product.

Of particular concern is moisture transfer between components with different water activity," continues Chaudhari. Other interactions that can affect the sensory quality of a product include the migration of coloring, fats, oxygen and other flavoring substances, plus the breakdown of vitamins and minerals is also a concern. These changes present further challenges to taste and limit a products shelf life."

Joey Talbert, senior food scientist, International Food Network (IFN), Ithaca, NY, says: We have incorporated vitamins, minerals, antioxidants, probiotic cultures, omega-3 fatty acids and enzymes into a variety of dry, liquid and semisolid foods. But to successfully do this, we must first identify the driving factors of degradation, then evaluate methods of prevention or reduction, and finally prove that a specific combination of technologies is effective in protecting the active ingredients.

While some nutrient losses in processing can be quickly identified and overcome by adding overages, the larger challenge is to predict the stability of the nutrients over prolonged periods of time," adds Talbert. Developing a predictive model is not that easy. The kinetics can vary greatly based on the nutrient, delivery format and packaging materials."

Walt Zackowitz, marketing director, specialty ingredients, IFP Inc., Faribault, MN, says: Defining conditions that an ingredient must survive and what catalysts are available to accomplish release are critical factors when determining how to protect functional ingredients. You want to make sure the ingredient gets to the consumer in order to reap the benefits promised."

All wrapped up

Microencapsulation describes the process of enrobing one or more materials (the core) in another (the shell) at the microscopic level. Encapsulation technologies include spray drying, spray cooling, air-suspension coating, extrusion, freeze drying, coacervation, co-crystallization and more. The retention of the core is governed by its chemical functionality, solubility, polarity and volatility.

Microencapsulation is an enabling technology that allows sensitive ingredients to be physically enveloped in a protective matrix or wall material," says Anand Sundararajan, principal scientist, Martek Biosciences, Winchester, KY. Depending on the ingredient being encapsulated, this physical barrier can be beneficial in a number of ways. It can protect against oxidation, which could lead to sensory or nutritional deterioration. It can mask objectionable flavors, as well as minimize ingredient interactions that could lead to oxidation. And in some instances, microencapsulation provides controlled release."

The core of the encapsulate may be composed of just one or several functional ingredients, and the protective shell may be single or multilayered. The encapsulating material keeps the active ingredient locked in and stabilized until the desired time of release. To properly utilize encapsulation technologies, proper selection of coating materials, encapsulation process and handling ensures a consistent functional ingredient.

Encapsulates can be engineered to have specific release behavior that is appropriate for a given application," explains Kristine Lukasik, manager, scientific and technical product support, Balchem Corp., New Hampton, NY.

Depending on the properties of the core, the encapsulating material and the encapsulating process, different types of particles are obtained. The simplest is a small sphere surrounded by a coating of uniform thickness with diameters ranging from a few micrometers to a few millimeters. However, they can also bear little resemblance to these simple spheres. Both the size and shape of formed microparticles depend on the materials and methods used to prepare them.

Sometimes the particles are irregularly shaped, or there may be several distinct cores within the same capsule, as well as multi-walled microcapsules. Another possibility is to have several core particles embedded in a continuous matrix of wall material.

Encapsulation is the most widely used technology to protect ingredients," says Zackowitz. Advancements in encapsulation technologies allow for most of todays food ingredient encapsulates to contain 70% to 85% active ingredient, as compared to only 50% a mere decade ago. They also have more-consistent survival levels and are produced at lower cost."

Encapsulating systems typically fall into two categories for food applications: hot-melt coatings and water-soluble coatings. Coatings must be compatible with the application. An oil-encapsulated ingredient will not release in a water-based system, while a starch-encapsulated ingredient will not release when heat is applied.

Hot-melt coatings have temperature-release capabilities, but they can also be designed to release by fracture (chewing, mixing), time or pH," says Tom Tongue, director of product development, IFP. Fully hydrogenated oils that melt between 135 and 155°F remain the most-common and cost-effective hot-melt coating materials, but modifiers such as partially hydrogenated oil, emulsifiers and waxes are effective tools, as well.

For example, some waxes offer a higher melt point than vegetable oils, so they can be used by themselves or blended with vegetable oils to survive higher-temperature environments," continues Tongue. Water-soluble coatings are most typically maltodextrins, starches, gums or emulsifiers used separately or in combinations to achieve specific performance characteristics or meet labeling requirements.

IFP utilizes a modified form of conventional fluid-bed encapsulation," continues Tongue. This technology applies layers of coating droplets onto the surface of the functional ingredient, creating a multilayer coating shell. The modifications allow us to improve the properties of conventional fluid-bed coating. The coating is created by applying dropletsversus head-on collisionin such a way that they wet-out the surface of the active ingredient, creating wider and thinner laminant layers that provide extended protection or improve fracture survival properties."

Its worth it. Special protection, such as encapsulation, will usually increase the ingredient price, but generally the value of the protection outweighs the cost.

By using encapsulated functional ingredients, manufacturers ensure the consumer that these nutrients are present in the final product," says Brian Bolluyt, president, Vobis LLC, Easton, PA. Further, not only do they remain viable, they wont interact with other ingredients or oxidize, both of which can result in the formation of off flavors, off colors and even product degradation during shelf life."

Microencapsulation is a useful tool in the beneficial fatty-acid business, allowing products to be developed that previously were not possible. In liquid applications, microencapsulation can be used to protect active ingredients through the formation of micelles," says Brenda Rudan, group leader, IFN. With omega-3 fatty acids, hydrophobic groups form the inside layer of the micelle, while hydrophilic groups form on the outside of the micelle to help emulsify the component in solution."

Sundararajan explains: Our algal DHA (docosahexaenoic acid) oils and powders contain polyunsaturated fatty acids that are highly susceptible to oxidation. To protect them, we minimize their exposure to oxygen, heat, light and transition metals during the manufacturing process and during product handling and storage, and in addition by using antioxidants, microencapsulation technology and low-temperature storage."

Similar to omega-3 fatty acids, conjugated linoleic acid is also rich in polyunsaturated fatty acids and, therefore, sensitive to oxidation.

Other protective measures

Its helpful to provide additional stability by adding antioxidants to the food matrix, notes Patrick Luchsinger, marketing manager, North America, Lipid Nutrition, Channahon, IL. Weve also developed an omega-3 fatty-acid emulsion suitable for addition to liquid products," he says. Proprietary technology, which includes encapsulation and the addition of antioxidants, renders the emulsion highly stable, allowing it to be added prior to heat treatment. It is especially well suited for long-shelf-life products, including milk beverages processed by direct UHT pasteurization (298°F for 4 seconds) or HTST or extended-shelf-life pasteurization (248°F for 4 seconds) followed by flash cooling."

Processing can also aid stability. As a polyunsaturated fatty acid, ALA (alpha-linolenic acid) can present stability issues if not processed properly, resulting in a rancid taste," says Marilyn Stieve, business development manager, flax, Glanbia Nutritional Inc., Fitchburg, WI. Our unique stabilization process is based on seed sourcing, cleaning and processing." She notes removing immature and off-colored seeds helps minimize oxidation, as does the milling process, which protects the seed matrix. We also incorporate natural antioxidants into certain flaxseed blends to further improve stability," she says.

Such protective efforts by functional-food ingredient suppliers have allowed the development of products previously considered technically unfeasible. Antioxidant and encapsulation technologies will continue to allow new innovations in the health-and-wellness food and beverage categories.

Donna Berry, president of Chicago-based Dairy & Food Communications, Inc., a network of professionals in business-to-business technical and trade communications, has been writing about product development and marketing for 13 years. Prior to that, she worked for Kraft Foods in the natural-cheese division. She has a B.S. in food science from the University of Illinois in Urbana-Champaign. She can be reached at [email protected].