Micronutrients for Value-Added Designer Foods

Micronutrients for
Value-Added Designer Foods
February 1997 -- Applications

By: Stuart Cantor
Contributing Editor

    A body of scientific evidence is rapidly accumulating that shows a wide variety of food components -- vitamins and minerals, herbals and other ingredients -- have beneficial effects on human health and well-being. Over the last few years, the food industry has launched many products that capitalize on this relationship. New-age beverages fortified with antioxidant vitamins have splashed onto the market.There are candies, power bars and even chewing gum with added natural herbal ingredients like ginseng.

  Food product designers have been busy, not only trying to improve the stability and functionality of these "new" ingredients, but also formulating innovative foods that will entice consumers with their "good-for-you" auras and health benefits.

A new era in labeling

  With the increased use of nutrients in food products has come a change in food labeling regulations. First, the Nutrition Labeling and Education Act of 1990 (NLEA) was enacted by the U.S. Food and Drug Administration (FDA). The NLEA mandates that all processed foods bear a more comprehensive and easier to understand nutritional panel. Currently excluded from these regulations are foods with insignificant amounts of nutrition, such as coffee, tea and spices, along with medical foods and dietary supplements (except in food form). The NLEA established two sets of label reference values -- reference daily intakes (RDIs) for vitamins and minerals and daily reference values (DRVs) for six food components based on a 2,000- or 2,500-calorie diet.

  The FDA recently enacted a ruling concerning the B vitamin folacin. Enriched breads, pasta, flour and other grains must be fortified with folate (0.34 to 1.40 mg per pound) no later than January 1, 1998. Folacin decreases the risks of neural tube defects and other birth defects and may also help those at risk of cardiovascular disease.

  Currently, a specific health claim stating that the antioxidant vitamins (C, E and ß-carotene) reduce the risk for certain types of cancers, heart disease and other conditions has yet to be approved. According to David Snyder, technical services manager, Roche Vitamins, Inc., Paramus, NJ, after January 1997, an established RDI of 80 µg/day for vitamin K will go into effect. However, it will still not be mandatory to add it on the label.

  Because the fine line between a food or a dietary supplement is sometimes blurred, the Dietary Supplement Health Education Act of 1994 (DSHEA) was passed and will be enforced as of January 1, 1997. Briefly, a dietary supplement is any of a number of products used to supplement the diet by increasing the total dietary intake of important nutrients.

  Herbal ingredients have begun to appear more frequently in food products since the passage of the DSHEA, says Fran Ertl, vice president technical service, Botanicals International, Long Beach, CA. "It used to matter whether an herb was GRAS (Generally Regarded as Safe) or not," she says. "Before, if an ingredient was not GRAS, the FDA could pull the product that contained it from the market. With the DSHEA, this is no longer an issue because this act defines botanicals as dietary supplements and products can now be sold and marketed under this category."

  Morris Glazer, technical service manager, Chart Corporation, Paterson, NJ, says that the DSHEA has opened a door for the food industry. "The FDA hasn't decided which way it will go," he says. "In the future, it may require the quantities of active ingredients to be listed on the label or it could even agree to allow certain health claims pertaining to the structure or function of the body to be made for an herbal ingredient." Glazer adds that for now, as long as the word "cure" is not used, companies can make a carefully worded health claim.

Magnificent micronutrients

  Micronutrients are substances such as vitamins and minerals that are not synthesized by the body but are necessary in minute quantities to sustain life. The micronutrient concentration of foods varies widely with maturity; variety is also influenced by food processing methods and storage conditions.

  Several essential minerals are also referred to as trace elements, including zinc, copper, cobalt, iodine, manganese, magnesium, iron and chromium. Many of these elements serve as cofactors in important metabolic reactions. Chromium, for instance, has been hailed as an important mineral for athletes interested in increasing muscle mass. Cobalt is an essential part of the structure of vitamin B12. Kevin Mulvehill, manager, food premixes, BASF Corp., Mount Olive, NJ, points to selenium as another "hot" trace element. Many studies show its efficacy at reducing the risks of certain cancers due to its antioxidant properties. He adds that the elements molybdenum (important as a cofactor in some enzymatic reactions) and chromium will become part of the U.S. RDI in 1997.

  Because these nutrients are required in only small amounts, it is important to get the maximum "bang for the buck." Bioavailability, still a controversial subject, refers to the body's ability to fully utilize a given nutrient after digestion. The presence of complexing substances, such as fiber, solubility, reactivity, stability and other factors can hamper a nutrient's effectiveness. While the concept of bioavailability is very important in formulating products requiring the delivery of optimal nutrition, Aileen Haig, technical manager, Daminco, Mississauga, Ontario, Canada, says it can be a drawback since bioavailability is often synonymous with increased reactivity.

  Reduced iron, a fine black powder, is fairly stable and less reactive than other forms, but it is not very bioavailable. "Because of its dark color and poor water solubility, this form would not be used in a beverage as it would settle out over time. However, it is used to fortify cereals and power bars," says Haig. "Ferrous sulfate or fumarate are quite bioavailable but also very reactive. These forms can readily oxidize other vitamins and color pigments to cause off-flavors and colors. Encapsulation can help overcome these problems."

  In general, the oxide forms of minerals are less soluble, but they are also less reactive. Other forms such as sulfates, glycerophosphates and lactates are more water soluble and can be used in beverages. "The correct market form of the mineral should be chosen carefully in order to be compatible with the product and its processing parameters," Mulvehill says. "With a thick, heavy meal-replacement beverage you could get away with a more insoluble mineral form, such as magnesium oxide. The product viscosity would support the insoluble minerals."

Phyto Power

  Remember when mom forced you to eat your vegetables before leaving the table? Some current scientific studies suggest that she may have had good reason. Phytochemicals, naturally occurring compounds present in fruits, vegetables, grains and legumes, are now being investigated for their disease-preventing characteristics. At this time, scientists are not sure whether the body requires such "nutrients" and in what levels. However, their presence in a product can pique consumer interest and help to distinguish it from the competition.

  Several phytochemicals and their proposed benefits are listed (See sidebar: Mother Nature's Pharmacy). Because of the low levels present in foods, it remains to be seen whether commercial production is feasible for most phytochemicals. Carrots contain only 8 mg/100 grams of ß-carotene and tomatoes have just 1 mg/100 grams of ß-carotene and about 6 mg/100 grams of lycopene. The carotenoid content of fruits and vegetables is low so ß-carotene is manufactured synthetically to be "nature identical."

  Carotenoids may play roles in preventing heart disease and cancer. They are effective antioxidants due to their extended system of conjugated double bonds that help absorb and inactivate free radicals. Beta-carotene is the most well known of the more than 500 carotenoids, which include canthaxanthin and lycopene. Only a few carotenoids are converted to vitamin A in the body. Recently, there have been studies to determine whether these phytochemicals warrant a specific RDI.

  Beta-carotene comes in many commercial forms; some are oil-soluble and some are water-soluble. Oil-soluble forms can color fats and oils, especially margarine. Water-soluble forms include dry gelatin beadlets with ß-carotene content of 10% that can be used in candies, baked goods or dessert toppings. Also available is a powdered granular version for aqueous systems containing a minimum of 1% ß-carotene for beverages, cake mixes, instant puddings or a salad dressing mix.

  "The 10% product gives you an orange color, the 1% gives you a yellow color. Our 10% B product gives you no color but is not soluble in water -- it was made for baking application and similar products," says Snyder. "The 1% or 10% water-soluble product is ideal in beverages because it is non-ringing if used according to directions. A ring, or layer, composed of coalescing ß-carotene oil microdroplets, can form on the surface of a beverage as it sits on the shelf. Consumers perceive this ring as a product defect or as spoilage." Snyder adds that for beverages, "It is a good idea to add approximately 200 ppm of ascorbic acid to act as an antioxidant and protect the ß-carotene."

Put to the test

  Established test procedures for the identification and detection of vitamins and minerals exist, but there is currently little information on testing botanicals. Most companies have spent years developing their own protocols in-house, says Ertl. "Plant materials are natural agricultural commodities with very complex chemistries. Because the products are all-natural, there will be variation in the amount of active compounds or phytochemicals present in the herbs."

  The most common analytical method for these ingredients is high pressure liquid chromatography (HPLC). Several extraction and purification steps are required prior to injection so that when the peaks elute from the HPLC column, they are narrowed down to the ones of interest. This minimizes interfering peaks. Gas chromatography/mass spectrometry is also used.

  Testing herbals involves two stages: identification and quantitation. "Identification involves taking a combination approach and using several tests together to ensure that the product is identified correctly," says Ertl.

  Tests include organoleptic evaluation, thin layer chromatography, microscopic image analysis, in which the ingredient can be checked for adulteration, and even identifying the taxonomic features of the plant. Ultraviolet/visible spectroscopy can be used since the active ingredients will absorb light strongly at certain wavelengths and fourier transform infrared spectroscopy can generate a "fingerprint" of the molecule.

  Testing becomes much more complicated with a food matrix, says Mark Lange, Ph.D., laboratory director, Industrial Labs, Denver, CO. More extraction procedures are required to isolate the vitamin or herbal component from interfering with macroingredients such as fiber, fat or protein. "Even during analysis, precautions must be taken to ensure accurate quantification of an ingredient," says August Martin, food laboratory manager at Industrial Labs. For example, when analyzing for ß-carotene or the vitamin A isomers, the heating time should be minimized so that the vitamins are not destroyed. Also, because vitamin A is light sensitive, dark glassware should be used and fluorescent overhead lighting should be replaced with weaker, yellow lights.

  While the U.S. Pharmacopeia (USP) is the "bible" for testing vitamins and minerals, there are currently no test procedures or tolerance limits dealing with quality control parameters for botanicals. The USP is being revised and when completed in about six months to one year, it will be much more extensive in test procedures for the herbals than the British Pharmacopeia, according to Ertl.

  Herbal extracts are standardized to contain a certain percentage of active or marker compounds. For many botanical extracts, research has shown that their beneficial effects result from the action of many compounds, sometimes acting synergistically, rather than alone. Currently, the precise ratio of compounds that produce the optimal effect remains unknown.

  "There is a transition in the herbal industry as companies move away from the ratio method of standardization done on a weight/weight basis, to assays that reflect the actual amount of active components present," says Neil Jans, vice president/general manager of natural ingredients, Hauser Chemical Research Inc., Boulder, CO. "One time a ginseng extract may contain 1% ginsenosides and another, because of the growing conditions, may have only 0.4%." Extracts can be assayed and certified to consistently contain at least the minimum concentration of marker compounds specified.

  "There must be a system of checks and balances in place to ensure quality control," says Adina Mayerhoff, director of product development and research, Futurebiotics, Hauppauge, NY. For example, to ascertain that an extract of the herb kava kava contains at least 30% kavalactones, the supplier is required to provide a Certificate of Analysis (C of A). The actual product is tested against the C of A. "The true test of a herbal supplement's effectiveness is whether the consumer derives benefits from taking it," Mayerhoff says.

Fortification formulation

  A number of different foods may be fortified with micronutrients. The technology used to formulate these products can be quite complex.

  For instance, says Wilfred Wells, director technical services, Sunkist, Ontario, CA, "While some calcium is naturally present in orange juice, one needs to watch out that not too much is added or it will form insoluble complexes with the pectin." He adds that in this application, it is important to select a more water-soluble version of calcium, such as calcium lactate.

  On the other hand, Audra Davies, director of product development, Watson Foods, West Haven, CT, notes that while dicalcium phosphate works well in a ready-to-drink powdered mix, it can cause grittiness and off-flavor notes in a juice beverage. "You wouldn't want to use this form of calcium in apple juice, for example, because it is relatively insoluble and it will cause haze formation and cloudiness," she says. According to Sam Sylvetsky, director of sales, Fortitech, Schenectady, NY, vitamins are more susceptible to oxidative degradation in a liquid system due to its larger surface area than in a powdered mix and this must be taken into account when formulating.

  Some people opt for a quick meal from a power bar. Says Davies, "Because of the very high levels of fortification in these products, the use of encapsulated micronutrients is vital in overcoming negative characteristics such as off-flavors."

  Typically, these products are cold-extruded so it is not an issue of high-temperature stability but one of flavor. "The packaging material plays a vital role in the stability of a power bar as it sits on the shelf," says Bunny Rickard, applications manager-beverages, David Michael and Co., Philadelphia. "Because oxygen can accelerate degradative chemical reactions among the nutrients, an aluminum/ PET material with a low oxygentransmission rate that acts as an oxygen barrier works well."

  Off-flavors from minerals can range from metallic to astringent and depend on the levels used. Increasing the sweetness can help to overcome unpleasant tastes. It can also be a good idea to encapsulate certain minerals along with the vitamins, particularly iron and copper. "These minerals can act as prooxidants, destroying sensitive vitamins like C, and can cause lipid oxidation," says Snyder.

  A variety of materials, including gum arabic, ethylcellulose, hydrogenated vegetable oil and gelatin can be used as encapsulating agents, says Marla Schoor, director of marketing, BioDar, Spring Valley, NY. The agent can be selected so as to not release the micronutrients until they can be absorbed in the intestine, so off-flavors cannot be detected.

  Encapsulating ascorbic acid helps it survive the baking process. A high melting point fat releases vitamin C at 152 to 160°F, the early stages of baking. "Although sugar and the dough matrix offer some protection, the combination of flour enzymes and a moist-heat environment is very destructive to this vitamin," says Mulvehill. The other alternative is to add overages at least two times the RDI. This vitamin may also be added post-processing in the form of a spray or glaze.

  Cereals are another popular fortified food. The severity of the extrusion processing conditions -- high pressures, temperatures ranging from 100 to 260°C, moistures of 10% to 60%, and oxygen exposure -- promotes varying degrees of vitamin loss. Specific overages compensate for losses and ensure that the correct amounts are present to meet the claims made on the label.

  "It is important to determine the correct amount of overage to add to prevent the risks associated with over-fortification, particularly with minerals and the fat-soluble vitamins," says Davies. "The amount of vitamin losses at each stage of processing would be totaled and this is the amount that would have to be added initially to survive processing."

  A nutrient premix is prepared by first blending those nutrients needed, typically folacin, biotin and vitamin B12, in only small amounts. This first dry blend is then added to a carrier, such as dicalcium phosphate, which also serves as a calcium source. Then calcium and other nutrients, which are required in larger quantities, are added and the premix is milled to ensure that all particles are the same mesh size so they do not separate out.

  Some ready-to-eat cereals are fortified in two stages. The nutrients typically added at the start as a premix are the most stable and include vitamins B6, B12, E, niacin, folacin, riboflavin, calcium pantothenate and minerals. The vitamins should be added at a point where they will undergo the least amount of processing. The heat sensitive vitamins, A, C, D and sometimes thiamin, are sprayed onto the cereal after the extrusion process. A very fine mist keeps the final moisture level down.

  A 26 Brix solution of sucrose or corn syrup solids is used to coat the water-soluble vitamins. "These solutes have film-forming properties capable of forming a very effective oxygen barrier," says Mulvehill. "It is important that the Brix be low since there is no heat involved in the spraying process that would thin out the solution viscosity."

In good taste

  Adding nutrients as well as ingredients such as soy protein to nutritional beverages "presents a double challenge to the food technologist to both effectively mask an array of potentially objectionable flavors and also produce a product with an acceptable flavor profile," says Birgit Mitsch, business development manager, Firmenich, Princeton, NJ.

  Adding furaneol, a flavorant that occurs naturally in a number of different fruits, works well in this application. It imparts a creamy, sweet taste that can mask both the grassy, earthy off-notes from the soy protein as well as those from the vitamins. The primary culprit of off-flavors in these products is thiamin, which contains sulfhydryl groups that can cause "meaty" or "eggy" notes.

  "Light" flavors like lemon, lime, strawberry or vanilla are not always effective for masking the medicinal taste of some nutrients. However, the "sweet" profiles of honey or vanilla can mask the astringent aftertaste of the echinacea herb, says Rickard. The "heavier" flavors such as grape, raspberry, maple and chocolate more effectively cover up the unpleasant taste of thiamin and other nutrients. They tend to be less volatile and hold up better under heat treatments.

  Minerals may interfere with the flavor system designed to mask their taste, says Fred Triolo, flavorist at Firmenich. Concentrated fold citrus oils are susceptible to oxidation. Copper and iron act as catalysts to potentiate oxidative degradation. Completely encapsulating the flavors makes them impermeable to oxygen and will enhance shelf-stability. Sequestering agents that bind minerals, such as EDTA, citric acid or a polyphosphoric acid, also help.

  According to Mike Gross, quality control manager, Celestial Seasonings, Boulder, CO, powdered herbs are generally insoluble and often have grassy, musty off-flavors. For beverages, a series of filtration steps can eliminate the undissolved particles and a liquid flavorant can be added to mask the objectionable notes.

  Understanding the chemistry and knowing the correct levels of micronutrients maximizes the value-added potential of the finished products. The nutraceutical industry is poised for tremendous growth. By the year 2001, the U.S. market for phytonutrients is projected to grow by 30% to $23.2 million in revenues, according to a report by the research firm Frost and Sullivan. More research needs to be done on understanding their mechanisms of action in health and disease and on how best to formulate with Mother Nature's pharmaceuticals.

Note: not included in this text version are two tables: "U.S. RDI Values for Nutrients" and "Mother Nature's Pharmacy." If you would like a copy of these tables faxed or mailed to you, please e-mail [email protected] with a request for the "February 1997 Applications tables." Be sure to include your name, address, fax number, etc.

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