What's new among antioxidants and preservatives?
Feb. 1, 2013
by Laurie Gorton
Some of the hardest-working ingredients toil at the lowest doses. Antioxidants and antimicrobials, rarely used at more than 1%, have the tough tasks of keeping baked foods and snacks looking, smelling and tasting fresh and in safe condition for eating.
For years, formulators could depend on widely available, inexpensive synthetic ingredients such as BHA, BHT, TBHQ and synthesized organic acids to take on these jobs. Today, however, consumers want natural ingredients, not those bearing chemical-sounding names or chemically produced. That trend makes the selection of antioxidants and preservatives more difficult, but several suppliers now offer good choices for these important functional ingredients.
Two big changes in bakery formulation — extension of shelf life and use of whole grains — cast heightened attention on the staying power and safety of foods.
For more than 20 years, North American bakers have focused on improving shelf life extension through enzyme technology. “As the use of extended shelf life enzymes increased, mold inhibitor usage in food products also increased,” observed Bill McKeown, vice-president of technology, AB Mauri, Chesterfield, MO. Enzymes that add 10 or more days to the staying power of fresh products do so by enhancing softness through greater moisture retention. The presence of more free water in the finished product, however, raises water activity levels and makes fresh items more susceptible to mold.
Whole grain formulations must include the entire kernel — bran, germ and endosperm. “The germ contains high levels of naturally occurring fat, which may increase the formation of off-flavors during shelf life,” explained Barbara Bufe Heidolph, principal, food phosphates, ICL Food Specialties, St. Louis.
She noted that similar risks apply to baked foods and snacks containing fats. “Both naturally occurring and added fats are susceptible to oxidation associated with reduction in shelf life and unacceptable sensory characteristics,” Ms. Heidolph said. For some baked foods, adding nutritionally beneficial, but less stable, free fatty acids such as the omega-3s may also contribute to shelf life issues.
Antioxidants guard flavor as much as they do quality. “Antioxidants are often associated with only delaying the onset of off-flavors and aromas,” said Roger Nahas, PhD, product director of antioxidants at
Kalsec, Inc., Kalamazoo, MI. “We determined that fresh flavors can also be maintained, thus increasing shelf life and consumer appeal.”
Although most antioxidants go into fats and oils before they reach the bakery, sometimes they may need to be added separately to formulations. “The goal is to prevent changes in the product, minimize oxidative impact and provide a fresh-tasting and textured product,” said Rodger Jonas, director of national sales, PL Thomas, Morristown, NJ.
Antimicrobials, like antioxidants, enhance the perception of freshness, but they do this by combating molds and other microorganisms. Their use, according to Brittany Bailey, product manager, Kemin Food Ingredients, Des Moines, IA, not only increases shelf life but also enhances food safety.
Mold inhibitors, however, are only part of the solution. Formulators must address attributes that contribute to mold growth, and food processors also need to consider plant conditions. Mr. McKeown cited product pH and water activity and called attention to cleaning practices within the facility. “Proper sanitation is necessary to assure consistent extended shelf life characteristics,” he said. “Only after these standards are implemented can formulators then optimize the product and processing steps needed to obtain shelf life goals.”
Additive ingredients that ensure food safety and keeping quality are normal components of many yeast-raised and chemically leavened products. What is different today is that ingredient suppliers produce and distribute not only traditional mold inhibitors and antioxidants but also clean-label products.
The clean-label introductions have taken place during the past decade, Mr. McKeown said. “Clean-label mold inhibitors are gaining traction as consumers seek cleaner ingredient legends on their food products,” he commented.
Another way to consider natural-source antimicrobials and antioxidants is as “label friendly” alternatives, in the words of Ms. Bailey. “As food safety becomes more of a priority in the industry, manufacturers are hungry for label-friendly alternatives that are backed by science,” she said. “Consumers demand labels that they can easily understand and ingredients they can recognize.”
Pat Jobe, technical and specialty ingredients sales manager, Clabber Girl Corp., Terre Haute, IN, said, “Such ingredients allow a ‘clean label’ by reducing or eliminating chemical preservatives.”
Instead of chemical synthesis, many of the clean-label antimicrobials that function as preservatives result from bacterial fermentation. Such fermentation products — propionic, acetic, lactic and similar organic acids — act synergistically in foods to inhibit growth of harmful molds and other microorganisms, Mr. McKeown observed.
AB Mauri offers clean-label products made by bacterial fermentation of corn syrup solids (Nabitor citric acid), wheat starch (Nabitor WS), potato starch (citric acid), whey (whey-based mold inhibitor) and corn ethanol (vinegar, Nabitor LCPF). “We avoid the use of any petroleum-based products or synthetic materials,” Mr. McKeown said. “Our bakery scientists use common household ingredients that can be included in our clean-label product lines.”
Vinegar provides a good example, and Mr. McKeown described it as “one of the earliest clean-label products and a great example of an ingredient that has been used as an antimicrobial for many years.” He observed that food processors not only put vinegar in food products but often use it as an equipment sanitizer.
About six months ago, Brolite Products introduced NI Natural Mold Inhibitor. “It is made from cultured wheat flour and naturally fermented lactic acid,” said
Ken Skrzypiec, Eastern vice-president of sales and director of technical services, Brolite Products, Inc., Streamwood, IL.
Clabber Girl’s InnovaFresh encapsulated fumaric acid goes one step further, Mr. Jobe explained. The lipid coating used for encapsulation isolates the antimicrobial in doughs, where it might inhibit yeast development. The heat of baking releases the acid to lower finished product pH and maximize the effect of calcium propionate in the formula or when applied afterwards.
DuPont Nutrition & Health, New Century, KS, introduced Natamax B natamycin, an antifungal compound produced by bacterial fermentation. The company improved natamycin’s solubility by complexing it with cyclodextrins. It is effective at low doses and neutral in flavor, according to Nathalie Brosse, global business director.
Science recognizes certain plants for their antioxidant and preservative qualities, and plant extracts account for a growing number of natural additives.
Consider licorice, a source high in phenolic compounds known to have antioxidant effects. ICL Food Specialties introduced Licresse licorice plant extract this past year. Its functional benefits include reducing rancidity and off-flavors, delaying oxidation, prolonging shelf life and stabilizing colors. “One of its key features is that, unlike some other natural antioxidants, Licresse has a flavor profile compatible with baked goods,”
Ms. Heidolph said. Sensory studies show the ingredient to be compatible even with simple or plain-flavored baked goods.
Kalsec produces natural extracts that function as antioxidants in baked and extruded foods such as cookies and bars. Use results in a 50% reduction in hexanal values compared with the control. Hexanal is a known marker for oxidation.
The Fortium line of natural plant extracts from Kemin Food Ingredients provides alternatives to BHA, BHT and TBHQ. “The extracts help preserve the appearance, taste and quality of food products without negatively impacting flavor, color or odor profiles,” Ms. Bailey said. These extracts are based on the company’s proprietary rosemary.
The company is also working on buffered vinegar derived from a natural source and providing “an optimized flavor profile that enhances product food safety with minimal sensory impact,” Ms. Bailey said.
PL Thomas offers plant-source antioxidants made from rosemary, pomegranate, apple and acai, among others. Several are associated with well-established health benefits. For example, P40P is 40% punicoside pomegranate extract; rhodiola rosea extract, which just received self-affirmed GRAS status, is recognized for its effect on sustaining energy. “In addition, we have EatFresh natural antimicrobial agent, which was just put on the Organic Materials Review Institute’s list of ingredients accepted for use in organic products,” Mr. Jonas explained.
Many yeast-raised and chemically leavened products commonly contain traditional antimicrobial ingredients. Some incorporate these materials in their doughs, while others receive a spray application after baking. “Our clean-label products are more conducive to yeast-leavened products based on their pH levels,” Mr. McKeown said, “but they are presently being used in many chemically leavened products, including tortillas.”
Suppliers also cited applications in a broad range of baked foods. “We have a number of products now using our natural mold inhibitor,” Mr. Skrzypiec said, listing bread, rolls, buns, pizza crusts and other flatbreads, bagels, sweet goods and English muffins.
The plant extracts, too, find wide use. One of the newest, licorice extract, is being evaluated in grain-based items as diverse as ready-to-eat cereals, batter- and breading-coated items, whole grain bakery mixes, tortillas, and pasta and noodles, according to
Ms. Heidolph. And Ms. Bailey cited use of natural plant extracts in cereal bars, crackers and cookies.
Plant extracts have also been successful in frying oils, allowing additional cycles of oil use, Mr. Jonas reported. “The key is matching the correct antioxidant with the specific application,” he said.
A comprehensive review of natural food antimicrobials was published in the 2012 edition of the Annual Review of Food Science & Technology. Authors V. Juneja, et al., covered animal, microbial and plant sources and how they work.
Depending on the composition of the natural antioxidant or preservative ingredient, such materials are often added with other dry ingredients. Some preservatives, however, can be dissolved for a surface spray treatment, while antioxidants can be incorporated directly into frying oils.
Composition also determines usage levels. For example, Brolite’s natural mold inhibitor consists of a mixture of cultured flour and organic acids, and its usage level is 1 to 3% (flour weight basis). Exact dosage depends on the moisture level sought in the finished product and the shelf life desired,
Mr. Skrzypiec said.
Considerably lower usage levels characterize the fermentation-derived preservatives. Encapsulated fumaric acid is recommended at 0.1% (flour weight basis). “Its addition reduces the levels of additives and preservatives needed to ensure freshness,” Mr. Jobe said.
It’s a fact of life that natural materials often must be used in higher proportions than the chemically synthesized materials they replace. “Typical use levels of traditional antimicrobials such as calcium propionate are 0.25 to 0.75%, flour weight basis,” Mr. McKeown said. “Clean-label product levels are typically three to five times the amount of traditional mold inhibitors.”
Conversely, the licorice plant extract is recommended for baked foods at 100 to 1,000 ppm (0.01 to 0.1%, flour weight basis), according to Ms. Heidolph. A study in pie crust, a high-fat product, found that it provided an Oxidative Stability Index (OSI) reading of 15 hours, compared with nine hours for the untreated control.
Adapting snack and bakery processes to use natural-source antioxidants and preservatives generally presents no substantial changes in conditions, according to the ingredient manufacturers contacted for this article. Most of these ingredients can be added directly with other dry materials; however,
Mr. Skrzypiec noted that Brolite’s blended product will require a bit more water to compensate for its cultured wheat flour.
Spray applications of ICL’s licorice extract will need modest agitation when dispersed in water to prevent it from settling, Ms. Heidolph explained. But when put into doughs, its solubility is no problem, and the natural antioxidant does not affect flour functionality or starch-pasting properties.
Consulting the ingredient supplier is a good idea when making the change to clean-label antimicrobials and antioxidants. “Usage depends on end product application,” Ms. Bailey said. “We offer different formulas and delivery methods, taking into account the different mixing procedures, baking and storage temperature, as well as end product pH.”
Choice is important, and Mr. Jonas emphasized that some ingredients are designed for the oils used in baked foods and snacks, while others are intended for incorporation into the dough itself. “The key is not so much to adjust the process conditions as it is to know when to add the antioxidant and/or natural ingredient,” he said. “Application to specific products means different use levels and whether to add it into the mix or onto the surface.”