Designing for Digestion

Its unlikely that greetings like Hello and How are you? will ever be replaced with Hows the old colon today? Yet few disorders affect as many people as those of the digestive system.
The National Digestive Diseases Information Clearinghouse, Bethesda, MD, reports that over 70 million Americans daily activities or work are adversely affected by a digestive disorder. The International Foundation for Functional Gastrointestinal Disorders, Milwaukee, WI, says one in four Americans are plagued daily by some functional gastrointestinal (GI) problem.
As if the pain and discomfort of conditions such as irritable bowel syndrome (IBS), dyspepsia, chronic diarrhea, and constipation werent enough, digestive issues affect other systems in our body: our immune system, nervous system, and our ability to stave off allergies and cancer risks.
As awareness of the importance of digestive health has increased, so has demand for products that support and improve it. And, con-trary to shoppers of yesterday, modern consumers are looking for digestion-friendly products beyond yogurt and bran muffins.

Friendly fiber
When speaking of improving digestion, or at least digestive output, fiber has been a common consideration for a long while. Who hasnt heard, Eat your fiber, it keeps you regular?
The term fiber refers not to a single ingredient, though, but a family of materials that serve to improve digestion and overall health in a variety of ways. According to AACC International, St. Paul, MN: Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine, with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances.
Fiber is classified as either insoluble or soluble, based on whether or not the fiber dissolves in hot water. Insoluble fiber, the more commonly known digestion helper, has long been hailed for maintaining regular bowel movements and reducing constipation. These distinctions persist despite more-recent studies that indicate additional benefits, such as reducing transit time of toxins through the colon and balancing colonic pH, both of which may help prevent colon cancer. Insoluble fibers include cellulose, hemicelluloses, and lignin, and can come from many plant sources.
Unlike insoluble fibers that pass through the system virtually unchanged, soluble fibers are affected on their journey through our sys-tems. Some form viscous gels in the stomach, slowing foods passage through the intestines, allowing for greater nutrient absorption. Additionally, hindering digestion and carbohydrate absorption reduces large swings in blood glucose levels and boosts satiety levels.
Soluble fibers are almost as plentiful as their sources: legumes; cereals such as oats, rye and bran; citrus fruits, as well as strawberries and apples; root vegetables; and psyllium husk. Functional soluble fibers, such as pectin, xanthan, acacia and guar gums, can be used to affect physical characteristics like viscosity.
Fibers can be utilized singly or in combination to achieve a variety of product characteristics. Some of our single-fiber ingredients include cellulose, cottonseed fiber, wheat fiber, bamboo fiber, sugar beet fiber, sugar cane fiber, natural oat fiber, inner pea fiber, potato fiber and microcrystalline cellulose, notes Jit Ang, executive vice president, International Fiber Corporation, North Tonawanda, NY. Of these, most are insoluble fiber, except sugar beet fiber, oat fiber, inner pea fiber and potato fiber. The latter fibers contain a mixture of predominantly insoluble components with some soluble components.
In some cases, modification of one material yields a new set of benefits. Partial hydrolysis of guar, for example, reduces the viscosifying effect and allows for addition at fortification levels without exceeding acceptable product thickness.

Pro-bacterial
With so many new products bearing the term antibacterial these days, it may be difficult for consumers to understand the concept of good bacteria. Probiotics, however, are just that. As defined by the Food and Agriculture Organization of the United Nations, probiot-ics are live microorganisms administered in adequate amounts which confer a beneficial health effect on the host. Probiotic cultures have been studied for positive effects on a variety of conditions ranging from allergies to IBS, prevention of kidney stones, and reduction of blood pressure, cholesterol, dental caries and cancer.

Probiotics' benefits, however, begin in the gut. Fermentation of indigestible carbohydrates provides short-chain fatty acids (SCFAs), the presence of which has been linked to reduced risk of inflammatory bowel disease, cardiovascular disease and certain cancers. SCFAs also reduce gut pH, which helps drive off pathogens and improve mineral absorption.
Most commercially utilized probiotic culture strains are of the genera Lactobacillus and Bifidobacterium, although there are addi-tional strains from other genera, including Escherichia, Enterococcus, Bacillus and Saccharomyces.
Typical dosage levels range from 5 to 20 billion CFUs per day. These levels do not necessarily reflect the amounts added to a food system, though, as processing techniques and conditions within the food can have a dramatic effect on the cultures ability to survive through shelf life.
One approach to ensuring proper levels at consumption is over-dosing. After studying the survival rate of the selected cultures in their product, processors can add an appropriate excess and ensure the required levels at the end of shelf life. However, with probiotics, quality is more important than quantity, says Mike Bush, vice president of business development, Ganeden Biotech, Inc., Mayfield Heights, OH. If the cells are not able to survive to colonize the host, even huge doses are not going to make any difference. In order for probiotics to be beneficial to consumers, the bacteria have to survive the manufacturing process, shelf life in stores and the acid in the stomach so they can colonize in the intestines.
Bush suggests a patented strain of Bacillus coagulans that actually protects itself. Due to the strains spore-forming nature, it has the ability to survive through both high and low temperatures, high pressure and shear, and a variety of pH ranges and water activities, he says. It is stable in a large variety of manufacturing processes that would ordinarily kill most other probiotic organisms, has a long shelf life and can endure the acids in the stomach to proliferate in the small intestine.
Improved stability and longevity open up many new application areas for prebiotics. Traditionally, probiotics have been delivered in cultured dairy products, notes Bush. This is due mostly to the fact that traditional probiotics survive well in the safe, refrigerated con-fines of these dairy products. Due to its ability to withstand extremes, such as heat and cold, high pressure and shelf stability, we have clients formulating it into baked products such as: muffins and bars; heated products such as soup, coffee, tea and oatmeal; and frozen products such as frozen yogurt.

Picky eaters
High dosage levels of the heartiest probiotic strains do not guarantee their survival or proliferation in the gut. Probiotic chow is a necessity, and it comes in the form of prebiotics. A special group of soluble fibers, prebiotic fibers, resist digestion and absorption in the gastrointestinal tract, are fermented by microflora in the gut, and stimulate growth and/or activity of at least one beneficial intestinal bacterium.

All prebiotics are not created equal. Origin and structure will affect fermentability by a given group of bugs. These differences can also yield additional health benefits, including improved mineral absorption and immune system function, increased resistance to infec-tion, and reduced risk factors for colorectal diseases.
Thermal polymerization of glucose yields polydextrose, an oligosaccharide (a chain of sugar molecules ranging from 3 to 10 units in length) often utilized to provide bulk, especially in reduced-fat and lower-sugar formulations. Partial hydrolysis in the small intestines yields low-molecular-weight polydextrose fragments, which probiotic organisms ferment into disease-fighting SCFAs such as acetate, butyrate and isobutyrate.
Bugs do not live by glucose alone, though. Exclusive enzymatic processing of lactose transforms individual sugar units into galacto-oligosaccharides (GOS), notes Sarah Staley, vice president, business development, Friesland Foods Domo USA Inc., Chicago. One uniquely processed GOS provides prebiotic benefits in a sturdy form that requires no special handling, she says. It is extremely heat- and acid-stable, unlike many prebiotics, which can be prone to breaking down on exposure to heat and low pH.
Staley notes that this specialized GOS, available in both syrup and powder forms, can be used in a variety of applications. It is extremely versatile and can handle harsh processing conditions, she says. Globally, GOS is often used in infant formula due to its simi-larity to human-milk oligosaccharides, as well as dairy products, juice and juice drinks, bars, and dietary supplements.
Powdered corn starch provides the starting material for digestion-resistant maltodextrin. According to Allan Buck, director of research and development, food ingredient research, ADM, Decatur, IL, one unique form of maltodextrin is over 90% soluble dietary fiber that escapes digestion in the small intestine and is available for utilization by intestinal bacteria in the large intestine. Although it is functionally and structurally maltodextrin, the linkages are not broken down by our digestive enzyme, he says.
Resistant maltodextrin has been shown to be a versatile option for increasing fiber content in an array of applications, including all types of beverages, cultured dairy products, frozen dairy desserts, confections, baked goods and other processed foods. It is highly soluble, with high clarity and low viscosity, and stability to high-temperature processing, even at low pH, Buck adds. This makes it ideal for clear, fortified beverages.

Fructose polymers ranging from 2 to 60 units long make up the inulin family, which includes fructooligosaccharides, typically meas-uring 10 units or less, and short-chain fructooligosaccharides (scFOS), at 2 to 4 units long. Found in many fruits and vegetables, inulin from chicory has become popular with food-product designers for its neutral taste, high solubility and low viscosity.
Another virtually invisible prebiotic fiber, soluble corn fiber, has physical characteristics similar to corn syrup, notes Michelle Schwenk, senior food scientist, Tate & Lyle, Decatur, IL. It offers prebiotic benefits in a highly soluble, clear, colorless and pH-stable powder or liquid. Soluble corn fiber is also quite well tolerated, which gives it more flexibility in application and levels compared to other prebiotic fibers, she says. Soluble corn fiber is very cost-effective, further opening up the applications.

Herb your enthusiasm
The ancient Greek pharmacopoeia listed peppermint and similar minty plants as digestion aids, relieving conditions such as indigestion, cramps, diarrhea, and symptoms associated with IBS and food poisoning. Research has also indicated peppermint oils effectiveness for relaxing GI smooth muscle and the lower esophageal sphincter. Peppermint is commonly used for flavoring products like tooth-pastes, mouthwashes and confections, as well as GI medications. Care should be taken when formulating for digestive functionality, as peppermint can be toxic at elevated levels.
Many traditional flavorings can be used to improve digestive health. A study published in the International Journal of Food Sciences and Nutrition (1996; 47(1):55-59) indicated: Dietary curcumin, capsaicin, piperine and ginger prominently enhanced intestinal lipase activity, and also the disaccharidases sucrase and maltase. Dietary cumin, fenugreek, mustard and asafoetida brought about decreases in the levels of phosphatases and sucrase. The positive influences of a good number of spices on these terminal enzymes of digestive proc-ess could be an additional feature of spices that are generally well recognized to stimulate digestion.
Some fruits can provide enzymes capable of improving digestive health. Central and South American cultures have long used pine-apple for improved digestion, a benefit of its constituent enzyme bromelain. Proteinases papain, caricain, chymopapain and glycine endopeptidase are found in papaya. Enzymes from both fruits are believed to be effective reducers of intestinal inflammation. Papaya proteinases have, however, been shown to be vulnerable to acid denaturation and subsequent proteolysis. Inclusion in food systems may, therefore, require protective technologies to ensure viability in the gut.
Aloe vera has, for generations, been a common healing agent for skin conditions. Modern studies suggest, however, that aloe vera gel may provide relief from inflammatory GI diseases such as ulcerative colitis (inflammation of the large intestine) and gastritis (inflammation of the mucosal lining of the stomach) by promoting the healing of gastric lesions and preventing damage from infectious pathogens, chemical irritants and GI reflux disease.
So, the next time youre eating out at your favorite restaurant, take particular notice of the basket of mints by the register on the way out. What if those treats treated more than bad breath? Soluble corn fiber can be used as an excipient, is directly compressible and can be mixed with a mint flavor and tableted, says Schwenk, to give about 1 gram of fiber in a 2-gram mint.
Mmmmm, digestalicious!

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.