September 26, 2011
By R. J. Foster, Contributing Editor
Consumers growing understanding of nutrition has caused a shift in attitudes about healthy foods. The 19th annual Shopping for Health" survey, conducted by the Food Marketing Institute, Arlington, VA, and Prevention magazine, indicates that consumers, in addition to avoiding undesirable elements such as saturated fat, sugar, sodium, calories, etc., are seeking products that contain specific nutrients. So, while consumers are looking for foods with healthy ingredients, manufacturers are turning to premixes as a convenient, consistent way to incorporate such ingredients into their products.
Addition of nutritional ingredients dates back to the mid 1900s. People perceived white flour as healthier than traditional untreated flours. The processing did eliminate disease-causing fungi, but also destroyed many of the nutrients present in the original grains. Interest in regaining the lost vitamins and minerals led to the evolution of enrichment," or replacing nutrients lost in processing. Today, FDA guidelines govern the content of thiamine, niacin, folic acid, riboflavin and iron in enriched flour.
Adding nutrients not originally present in a product, however, is referred to as fortification." Adding iodine to salt, iron to cereals and vitamin D to milk are well-known examples of fortification. Todays growing fortified-foods market, however, includes an array of applications. Beverages seem to be leading the way, followed by baked goods and whole-grain cereals," suggests Ram Chaudhari, senior executive vice president and chief scientific officer, Fortitech, Inc., Schenectady, NY. He notes that, while any food or beverage product can be fortified through the use of a premix, there is no one-size-fits-all approach to their formulation. Each product is unique, and how an ingredient interacts with the product and the other ingredients incorporated into the product varies and needs to be addressed in a customized fashion," he says.
Preformed for performance
Versatility is one major benefit of premixes. Powdered nutrient premixes are the most widely used due to supply-chain and stability issues," says Chaudhari. Liquid premixes, especially for vitamins like A, D, E and K, and carotenoids and other lipophilic nutrients, are delivered through liquid (oil) as a vehicle containing stabilizers, emulsifiers and antioxidants." Plated premixes have found use in uniquely challenging applications where hygroscopicity and stability issues have been observed. But this is a very limited category at this time, he says.
Premixes provide a convenient way to add a nutrient package that appeals to a specific target consumer. Energy blends commonly contain combinations of B vitamins, minerals, taurine and guarana. Antioxidant blends of vitamins A, C and E are ongoing favorites among health-conscious consumers. Of growing interest are blends designed to address specific health conditions: calcium, vitamin D, magnesium and vitamin K to stave off osteoporosis; lutein, lycopene, omega-3 fatty acids, thiamine, sterols and prebiotic fiber for heart-health; or conjugated linoleic acid, prebiotic fiber and green-tea extract for weight management.
Vitamins and minerals are chosen for their nutritional or functional benefits. The form of those ingredients, however, often depends on the products to which they are being added. Often perceived as more bioavailable, soluble ingredients are desirable for clear beverage applications where settling out would be a negative. High levels of citrates and chlorides can, however, increase hygroscopicity of a drink mix. Increased solubility also brings increased potential for adverse effects on flavor, color and stability.
Formulating for specific nutrient levels can be challenging with highly soluble sources. Achieving a 10% of Daily Value (DV) of calcium requires 1,120 mg of calcium gluconate (soluble), but only 250 mg of calcium carbonate (insoluble). Less-soluble materials have reduced potential for adversely affecting finished product taste, color, etc., and are able to carry counter ions that provide additional label-claim opportunities.
Selection of a nutrient source may also be based on reducing the potential for adverse reactions in the finished food. The iron source ferrous sulfate can promote oxidative rancidity in foods containing fats or oils," says Dave Pfefer, product manager, fortification, Caravan Ingredients, Lenexa, KS. Changing to reduced-iron powder can prevent this from occurring. Reduced-iron powder, which is dark grey or black in color, can, however, cause graying or discoloration of white or light-colored foods, so a switch to ferric orthophosphate may be the solution."
Preventing premix predicaments
Premixing multiple nutrient ingredients into a single ingredient streamlines production processes and eliminates potential batching or incorporation errors that could result in a nutrient deficit, regulatory issues and product recalls. One characteristic of nutrient ingredients that require a premix is their extremely low usage levels in the finished food product," Pfefer says. Some are contained at milligram or even parts per million levels that, if added directly to the finished food product, would be very difficult to disperse throughout the entire food mass at the required concentration within the normal mixing or blending time."
The number and variation of components can also challenge premix developers. The average premixes contain 10 to 15 active nutrients, and 3 to 6 excipients (carriers), many of which vary in particle size and bulk density. Imagine trying to create a uniform blend of 1 spoonful of granular sugar, 3 spoonfuls of flour and 5 spoonfuls of rice, then add to that blend a one-half teaspoon of salt and a quarter-spoonful of color," Chaudhari says. Presuming success in combining these ingredients into a homogeneous blend, the next challenge is compressing small amounts of the blend into a serving of a nutritional product."
In addition to homogeneity, premixes provide a means of protecting sensitive ingredients from each other. Within a premix, interactions between components can occur due to pH differences, moisture migration and redox reactions," Pfefer says. To counteract these tendencies, some of the reactants may be microencapsulated with various high-melting fats, starches, gums or sugars."
Encapsulation helps developers by dictating structure and release characteristics. Additionally, coating nutrients immobilizes and protects by increasing resistance to degradation by oxygen and heat.
Spray-drying transforms fluid materials into dry by mixing the original liquid ingredient with a dry carrier such as starch, and atomizing the combination into a chamber filled with hot air. Selection of the carrier is based on finished-product application. A blend destined for a cold-water-dispersible beverage mix will require a highly soluble carrier. Solubility is, however, typically of lesser concern in something like a nutrition-bar application.
Lipid encapsulation provides similar levels of protection for dry nutrients, reducing potential reactivity with other ingredients in the premix, as well as the finished-product matrix. Selection of the right kind of coating can preserve taste by limiting migration and preventing premature release of ingredients that can negatively affect taste and limit shelf life," says Chaudhari. Coating materials with higher melting points can allow developers to add a premix to an instant hot cereal without fear of adverse interaction in the dry mix, or premature release when hot water is added. High-temperature processing systems can, however, disrupt or destroy the lipid coatings, leading to the undesirable interactions described.
One of the very few attributes that vitamins have in common is that none of them are completely stable in foods," Chaudhari explains. The stability of the individual vitamins varies from relatively stable, such as niacin, to highly unstable, such as vitamins B1, A and C. The factors that affect the stability vary from vitamin to vitamin; the most important factors are heat, moisture, oxygen, pH and light."
To compensate, overages are often necessary. Overages are the increased levels of nutrients added to a premix to compensate for anticipated nutrient losses due to manufacturing the blend, due to processing the food, and due to natural decay during the extended shelf life of the food product," Pfefer says. By putting these higher levels in at the time of production, a manufacturer can guarantee that full label claims will be present at the end of shelf code."
The amount of overage required relates directly to the nutrients stability. Highly reactive ingredients, such as vitamin C in a beverage application prepared in an open (exposed to the air) system, can require over 100% overage. In a powdered application, though, the overage needed would be less, as nutrients in the solid state do not facilitate the cross-reactivity seen in liquids.
Chaudhari indicates that much new development in premixes is coming based on discovery of new effects from familiar ingredients. Protein, the longstanding ingredient of choice for body-building products, is being requested by manufacturers of weight-loss products due to its satiety-promoting ability.
Fiber, known for its heart-health benefits, is being used in weight-management products due to its satiety-promoting benefit, and in immunity-boosting products due to the impact it can have on digestive health.
Another ingredient that we are seeing a marked interest in is GABA (gamma amino butyric acid)," Chaudhari says. This is being more and more utilized in beverages designed to help one relax, due to the calming effect it has on the brain."
R. J. Foster is a wordsmith with a B.S. in Food Science from the University of Wisconsin-Madison and over 15 years of experience in the food industry. He can be reached through his website, wordsmithingbyfoster.com.
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