Functional fiber: a series of presentations from Prepared Foods' 2005 R&D Conference offered advice on the nutritional and formulation benefits of dietary fibers

Prepared Foods, Jan, 2006

Dietary fiber can play a positive role in helping to control cholesterol, blood glucose and body weight (the latter through appetite regulation). Regular consumption also may help reduce the risk of colon cancer, cardiovascular ailments and other diseases.

Fruit Fibers: Nutrition and Functionality Plant-derived dietary fibers are resistant to digestive enzymes in the stomach and small intestine. However, they are broken down completely or partially into catabolites by fermentation in the large intestine--for example, butyrate, which the human body absorbs and utilizes. Cereals, fruits and vegetables are the primary sources of fiber, said Frank Mattes, president of Herbstreith & Fox Inc., in his presentation on fruit fibers. The American Dietetic Association recommends a daily dietary fiber intake of about 1oz (20g-35g) per day, but average consumption is only half an ounce.

Fiber addition can be based purely on physiological aspects, but fibers also offer technological benefits. In addition, fruit fibers can influence food rheological properties.

Three factors--plant type, specific plant tissue and manufacturing process--strongly influence the physical and chemical properties of dietary fiber ingredients, such as water and ion binding, solubility, swelling, flavor and nutritional benefits. Depending on the refinement process, fruit fibers are characterized by the flavor of the source fruit. Additionally, these fiber products also carry high amounts of secondary plant substances, such as flavonoids. Research indicates these compounds may strengthen capillary resistance, prevent oxidation of low-density lipoprotein (LDL) cholesterol, chelate heavy metals and prevent ascorbic acid oxidation.

Fruit fibers derived from apple, citrus and other fruits with a high content of soluble fiber have relatively good water-binding and -swelling properties. They can help provide a smooth mouthfeel in products. Greater purification of these ingredients increases fiber content and produces products with a more neutral taste. Their higher water-binding capacity means they can thicken and stabilize products.

Their cold-swelling properties mean they are readily dispersible and easy to handle in production. The fibers are shear-stress stable, and the texture formed has good heat and freeze/thaw stability. With their extraordinary swelling capability, fruit fibers are an ideal base for beverage powders or fiber bars that promote weight reduction. It also is possible to produce reduced-calorie ice cream with a pleasant mouthfeel and enhanced stability. Replacing fat with fruit fiber ingredients can result in low-calorie sausages. Other application areas include dairy foods such as low-fat cheese products. In bakery products, calorie reduction and water-binding are of interest, resulting in extended shelflife.

"Fruit Fibers: Nutrition and Functionality," Frank Mattes, Herbstreith & Fox Inc., f.mattes@herbstreithfox.com, www.herbafood.de

A Glycemic Index-reducing Prebiotic

Acacia gum can be used to create healthful products of increasing interest to consumers. A greatly expanded growing region in sub-Saharan Africa has resulted in a consistent supply of this all-natural fiber, noted Sebastien Baray, U.S. technical manager with Colloides Naturels Inc., in his presentation "Fiber Fortification with Acacia Gum."

Baray recounted a variety of nutritional trends: One third of U.S. adults consider their diets deficient in fiber, and there is a strong understanding of the link between fiber and overall health. Also, insulin resistance and diabetes are approaching epidemic status, with diabetes cases expected to increase 19% between 1999 and 2010 world wide. Four out of 10 consumers are aware of dietary fiber's role in prevention and management of diabetes, and 18% of U.S. consumers say they look for a Glycemic Index (GI) on food labels, he said.

An ideal nutritional ingredient is of relevant nutritional interest to consumers, is supported by scientific data, has a natural origin, is compatible with industrial processing and results in an enjoyable food with no negative side effects. Acacia gum is an all-natural, non-genetically modified (GM) fiber that meets all of these criteria.

The molecular structure of acacia gum consists of polysaccharide sub-units attached to a proteinaceous core. This complex structure explains the low viscosity and high resilience of the fiber. Acacia gum can be used to fiber-fortify products with no negative impact on their texture.

Research (C. Cherbut, et al., 1999) with 10 human subjects consuming increasing amounts (10g-70g/day) over 100 days showed lowered negative symptoms such as bloating, .flatulence and cramping compared to fructo-oligosaccharides, with symptoms generally not appearing until doses neared 50g/day. The same study demonstrated acacia fiber's prebiotic benefits--at 10g and 15g/day, there was a four-fold increase in "friendly bacteria." Another study (Rochat, et al., 2001) showed acacia gum had a prebiotic effect at only 6g/day.