The importance of fiber in the diet for maintaining good health has been recognized world over by now. Like water, fiber cannot be strictly classified as a nutrient essential for growth but while water is essential for the very survival, fiber consumption can dramatically influence the quality of life in many ways. The modern "mantra" about consuming whole grains, fruits, vegetables and nuts is based on the indisputable fact that they are rich sources of fiber. A daily intake of 25 gm for an adult is accepted in many parts of the world as essential for normal health..
The euphoria about dietary fiber has spawned many new businesses and there are thousands of products now available in the market claiming to be rich in dietary fiber that can control cholesterol, CVD, diabetes, hypertension and gastrointestinal afflictions. By far strongest evidence has come for the role of dietary fiber in reducing significantly the serum cholesterol level. The role of fiber in maintaining a healthy gut system and generating some nutrients like essential fatty acids are also well documented. Fiber contained in oat bran, whole wheat, beans, prunes and many plant foods are recognized as most effective in obtaining many of the benefits attributed to it.
Though there is distinct difference between soluble and insoluble fibers, both are required for good health. Recent differentiation between dietary fiber and functional fiber was necessary because of the tendency on the part of the industry to use some natural and others man-made substances in product formulations exhibiting some of the benefits of naturally occurring fiber sources. Two important sources of functional fiber are Polydextrose and Inulin,used widely by the food industry for boosting fiber content in processed foods. Polydextrose is made by vacuum melting of glucose with Sorbitol and citric acid resulting in a 3-dimensional structured molecule which resists action of gut enzymes that hydrolyzes starch and other carbohydrates. It is claimed as a soluble form of dietary fiber though every one does not agree that it is a true dietary fiber.
Polydextrose is water-soluble and is used in many beverages with a few advantages. It has a neutral, fresh taste, high solubility and good stability at a wide range of pH conditions. It is also stable at reasonably high temperature conditions without getting hydrolyzed easily. A solution of Polydextrose is clear and transparent in appearance with medium viscosity. Recently reports from China indicate that Polydextrose is an excellent additive for tea to modify the flavor and mouth feel liked by consumers besides contributing to higher levels of functional fiber. The low caloric value of only 1 kC per gm is an advantage while using in formulations with calorie restriction. The relatively low Glycemic Index, less than 7, makes it ideal for diabetic food formulations. Specialty foods incorporating sugar substitutes like aspartame need bulking agent or a carrier with least calorie content and Polydextrose fits into this role admirably.
With an E number of 1200, Polydextrose is widely used in many products where features like low caloric density, increased fiber level and reduced fat content are desired. Such products include beverages, cakes, candies, dessert mixes, breakfast cereals, frozen desserts, puddings, salad dressings etc. Being a humectant, stabilizer, thickening agent and a proven pre-biotic substance, Polydextrose offers opportunities for creating new foods with more diverse sensory characteristics. A few side effects attributed to this food additive include abdominal cramps, bloating of stomach and excessive generation of gas. Consumption of Polydextrose up to 90 gm a day does not cause laxative effect while other pollyols exerts such effects at levels less than 20 gm. Though it is proved to be safe for human consumption, having shown no deleterious effect so far by any scientific studies and approved for universal use as a food additive since 1981, considering that it is a synthetic product created out of chemical reaction, its use should preferably be restricted to specialty foods targeted at over weight, diabetic and diet conscious consumers.