One of the top trends in foods for 2007, if not the top trend, is nutritional health. Healthy products, which up until recently have been referred to as “functional foods,” include items that enhance immunity. Many ingredients have been found to enhance immunity and are popping up in new products on store shelves everywhere. Some of the more common ingredients are discussed here.
Prebiotics are indigestible food ingredients that encourage the growth of bacteria as they pass through the digestive system. Their role in improving immunity is a subject of great interest to food manufacturers.
“Prebiotics enhance the immune system in two ways,” states Lorraine Niba, business development manager for a well-known starch supplier. “First, by enabling the growth and proliferation of beneficial bacteria, the pathogenic and harmful bacteria are depleted and destroyed. Secondly, fermentation of prebiotics produces short chain fatty acids and lactate, which lower intestinal pH and maintain integrity of the epithelial cells that line the colon (colonocytes). This lower pH and stronger colonocytes protect against the harmful bacteria,” she adds.
“Prebiotic fibers have many sources and are naturally found in grains like wheat, corn, oats and barley; legumes like beans, peas and soybeans; fruits and vegetables like apple and grapefruit pectin; and roots like chicory. Milk oligosaccharides also have prebiotic activity,” offers Niba. “Many new ingredients are showing great potential as commercial prebiotic fibers. These include: isomalto-oligosaccharides (which contain a combination of isomaltose, isomaltotriose and panose), soy oligosaccharides (raffinose extracted from soy whey) and xylo-oligosaccharides,” Niba explains.
Easily incorporated into foods and beverages, many prebiotic fibers are water-soluble, disperse extremely well and can be added to a wide variety of foods and beverages such as breads, baked goods, nutrition bars, dairy products, soymilk, fruit juices and smoothies.
Soluble corn fiber and resistant starches are promising prebiotics that offer a variety of benefits to both producers and consumers. Prebiotic soluble corn fiber is a smaller molecular weight compound than resistant starch, and the 1-2 and 1-3 linkages cannot be broken down in the human body. Resistant starches are protected from digestive hydrolysis by three methods: seed coats, specific intact granule structures, or crystallized or retrograded non-granule structures.
“Soluble corn fiber has been found to increase the numbers of probiotic organisms found in the large intestine. These organisms can ferment the soluble corn fiber to produce beneficial fatty acids such as butyrate, which is a fuel for intestinal cells and associated with intestinal health,” states Lisa Sanders, a nutrition scientist (R&D) for a well-known starch supplier.
“While there are no official recommendations for amounts of prebiotic fiber to be consumed in a day, soluble corn fiber has shown beneficial prebiotic effects at 12g to16g per day. It has been well-tolerated without adverse effects at doses equivalent to 100% of the daily value for fiber, which is 25g per day for women and 38g per day for men, according to the Institutes of Medicine,” states Sanders.
“Currently, studies are investigating the immune-enhancing effects of soluble corn fiber. In vitro studies show encouraging results, where it has similar prebiotic effects to inulin, a well-researched fiber for immune enhancement,” she adds.
“Soluble corn fiber can be successfully formulated into all kinds of foods and beverages. Easy to use, it is a transparent fiber, meaning there is no change to color or flavor. Functioning like corn syrup, it can be easily added wherever corn syrup is used. However, being non-sweet, it can also be used in savory applications as a bulking agent or for fiber addition. Calorie reduction is possible, as it is only 2Kcals per gram,” states Michelle Schwenk, food scientist at a supplier of soluble corn fiber and resistant starch.
“Resistant starch is the only starch that has prebiotic activity because it is resistant to digestion, and thus reaches the colon. Other starches are digested and do not reach the large intestine,” explains Niba. “When prebiotic fibers are selectively metabolized (fermented) by colonic bacteria, they produce short chain fatty acids with health benefits.”