Bakers who fortify products with ingredients containing high levels of antioxidants help give customers the tools necessary to maintain a healthful antioxidant status, which in turn mitigates the risk of developing chronic diseases. Scientists continue to study the role of antioxidants and their contribution toward disease prevention. The prevalence of research in the field indicates researchers do, in fact, recognize the positive role antioxidants play in combating oxidative stress–a phenomenon associated with the development of chronic diseases (e.g., cardiovascular disease and coronary heart disease) and factors associated with aging (e.g., memory loss).
Consumers are increasingly becoming more interested in foods that offer health benefits above and beyond
that for which they were initially intended–as long as these products provide added fortification in a natural way. A variety of common foods, such as fruits, vegetables, whole grains, legumes and herbs, are naturally rich, not only in vitamins and minerals, but also phytonutrients, or plant-derived chemicals that have inherent protective properties against disease. Phytochemicals not only include a vast array of compounds that induce action against harmful substances via hormonal activity, stimulation of enzymes and/or anti-bacterial effect, but many have antioxidant properties as well.
While many of these antioxidant-rich nutrients blend well in bakery products from both a flavor and functional standpoint, bakers must consider a multitude of processing parameters and stability issues when formulating products with these ingredients.
Antioxidants do battle
Oxidation is an essential process the human body uses to produce energy, but too much oxidation leads to oxidative stress. “Oxidative stress occurs when the system becomes seriously imbalanced in favor of oxidation, which can result from excessive production of free radicals and/or weakening of the antioxidant system due to lower intake, or production of endogenous antioxidants or increased utilization of such,” explains Ram Chaudhari, Ph.D., senior executive vice president, chief scientific officer and co-founder, Fortitech Inc., Schenectady, N.Y. Thus, antioxidant status can be defined as the balance between pro-oxidants that lead to oxidation and the antioxidant system that prevents it.
“Antioxidants are any substance that delays or inhibits oxidation damage to a target molecule,” adds Chaudhari. “Antioxidants protect against damage from free radicals by preventing the formation of excess free radicals; scavenging free radicals after they are formed and before they damage other molecules; and repairing or replacing damaged molecules. Our cells can survive free-radical attacks because they have developed antioxidant defenses. While some antioxidants, such as enzymes and proteins, are produced in the body, others, such as vitamins E and C, and phytochemicals, such as carotenoids and flavonoids, come from the diet.”
According to the California Dried Plum Board, Sacramento, the phenolic compounds found in fruits and vegetables not only influence sensory properties, such as color, taste (e.g., bitterness) and flavor (i.e., aroma qualities), but also comprise much of the antioxidant capacity associated with these foods. In addition, the California Dried Plum Board cites research from the University of California, Davis, that identified and quantified the main phenolic compounds in dried plums as neochlorogenic and chlorogenic acids–phenolic compounds associated with lowered incidence of heart disease by protecting low-density lipoprotein (LDL or “bad”) cholesterol from oxidation.
“When generally speaking of fruit, the skin serves as a way to protect the inner flesh from the hazards of nature,” says Doug Webster, technical services manager, Tree Top Inc., Selah, Wash. “There are several phytochemicals found in the skin that not only give fruit its color, but also function as antioxidants. These include anthocyanins, flavonoids, tannins and a number of other phenolic compounds that minimize oxidation attack by free radicals.”
Ingredients of substance
Oxygen Radical Absorbance Capacity (ORAC) is one of the most widely accepted methods used in measuring antioxidant activity. In 2004, the USDA published an updated list of ORAC values for common foods that now includes a total ORAC value for both lipid-soluble and water-soluble phytochemicals. Lipid-soluble values were previously omitted, making previous data less accurate than current data. Caution should be taken when comparing ORAC values of different foods, as some evaluations may be based on dry weight, while others are based on wet weight or serving size.
Blueberries, which rank near the top of the list of common foods with high antioxidant levels, contain phenolic compounds, particularly those categorized as flavonoids, such as anthocyanins–the phytochemical that gives the fruit its characteristic bluish-red color. A range of blueberry formats are available to meet manufacturers’ needs including fresh, frozen IQF and straight pack, dehydrated, canned, juice, concentrate and puree.
The liquid products (i.e., juice, concentrate and puree) can be used in innovative ways in the baking industry. For instance, liquids can be incorporated into tortillas, bagels, muffins and breads to create blue-colored products. Drum-dried powders can be used for dusting baked products and bars or as a component of a bakery mix.
“Apple and other fruits are available fresh, frozen or processed into concentrated juices, purees or dried fruit products,” says Webster. “Dried fruit ingredients are readily introduced into baked goods as inclusions in the dough. Juice concentrates, purees and dried fruit powders can be used to bind water or serve as a component of filling. Fresh and frozen fruit is traditionally used in baked products, such as pies and sweet breads. In addition, the fruit industry is starting to capture fruit pomace and process this into a source of fruit fiber. Dried apple fiber, which is primarily peel, can be used in breads, crackers and other baked goods to increase fruit and total fiber content.”
When considering an antioxidant system in a bakery product, consider the ingredients inherent in the product. For instance, whole grains and certain herbs and spices contain phytonutrients. Other important components for consideration include fruits and vegetables rich in phytonutrients, as well as the following nutrients suggested by Chaudhari: tocopherols and tocotrienols (i.e., vitamin E); vitamin C; vitamin A and carotenoids; lycopene and lutein; selenium; coenzyme Q10 and glutathione.
Surviving the process
“Fortification, in general, is a reliable, safe and low cost way to improve food value–including baked goods,” says Chaudhari. “While fortification enables consumers to vary components in a healthy diet more easily, there are a variety of technical challenges that arise, particularly if manufacturers are using premixes with multiple ingredients. Each nutrient has its own characteristics that may impact flavor, ingredient stability and color. Because there are a number of factors that impact the stability of nutrients and their retention in foods, such as temperature, moisture, pH, oxygen, bioavailability and ingredient interactions, Fortitech urges product developers to thoroughly investigate nutrient characteristics prior to incorporating them into products.”
Bakers should use caution when formulating with heat-sensitive nutrients. Microencapsulation is one means of dealing with these types of ingredients, where a protective coating preserves the nutritional integrity of the ingredient contained within an inner core. Chaudhari also suggests adding heat sensitive ingredients at a different place during production, for example, during the coating process, so they are subject to lower temperatures.
Assessing the antioxidant capacity of a product varies, depending on the form of ingredient used and how the finished product is processed. For instance, although fresh blueberries retain the highest level of antioxidant activity, heat-processed products, such as pies, still retain a significant level as indicated by the U.S. Highbush Blueberry Council, Folsom, Calif. In terms of drying techniques, freeze-drying is the least harsh method, which minimizes the loss of antioxidant activity.
Among the U.S. Highbush Blueberry Council’s recommendations for using blueberries in baked products are conditions that stipulate that block-frozen berries thaw under refrigeration. The thawed berries should be stored in an airtight container and should never be refrozen. When incorporating IQF berries into batter, avoid overmixing to prevent breakage and bleeding, and bake the product immediately to prevent color leaching.
One way to minimize the spread of blue color throughout the batter is to deposit half the batter into the pan, followed by the addition of blueberries, then deposit the remaining batter and top with blueberries. Some bakers coat blueberries with flour or starch to soak up the juices before adding the fruit to the batter. In addition, a thick, dense batter will prevent blueberries from sinking to the bottom of the pan, but caution must be taken to avoid incorporating too much air into the batter, particularly during the first stage of mixing.
Regardless of the ingredient used, bakers must carefully evaluate all processing and storage parameters to ensure the highest possible integrity of the finished products. Fortunately, many antioxidant-rich ingredients are easily incorporated into baked products and are highly valued by consumers, not only for their health benefits, but for their flavor contributions as well.