Understanding polydextrose and how it works

Glucose is the sugar in our blood that supplies us with energy. When dozens of glucose sugars are linked together, it’s called starch. But there are ways glucose units are joined that makes them indigestible, and for some applications that can be a good thing.

We can’t derive energy from grass because the glucose sugars that make up the cellulose, which is structurally similar to starch, are linked together by bonds our digestive enzymes cannot break. Cellulose thus passes undigested into the colon where it functions as an insoluble fibre.

In the mid-1960s, Hans Rennhard, a Pfizer researcher, created a polymer of 89 percent glucose, 10 percent sorbitol and 1 percent citric acid that functioned as a soluble fibre. After patenting in 1973, and FDA approval in 1981, polydextrose was classified as a soluble fibre. Multiple studies have demonstrated its safety and positive effects on digestion.

Yielding only 1 kcal/g, polydextrose has become a multipurpose ingredient helping ingredient manufacturers increase non-dietary fibre content while replacing portions of a product’s sugar, starch and fat. This, in turn, helps food and beverage makers create products with reduced calories and lower energy density in a variety of foods, including beverages, cakes, candies, dessert mixes, breakfast cereals, frozen desserts, puddings and dressings. It’s also been a boon to low-carb and sugar-free creations.

Commercial polydextrose is available under brand names such as Sta-Lite by Tate & Lyle; Litesse by Danisco, now a division of DuPont Nutrition and Health; and Trimcal from C&H Ingredients, as well as others.

Last year, Nutrition Reviews published “Dietary fibre type reflects physiological functionality: Comparison of grain fibre, inulin and polydextrose.” The authors compared the effects of these different fibres on digestion and various blood parameters. The article compared the physiological effects of three types of dietary fibre with varying compositions, degrees of chemical and structural heterogeneity, origins and physical properties.

There are obvious differences. Grain fibre is chemically heterogeneous. It has both insoluble and soluble fractions, along with associated compounds, each promoting various biological activities.

In contrast, inulin and polydextrose are industrial products that must demonstrate their beneficial physiological functions in order to be classified as dietary fibre. Inulin is a soluble fructose polymer that promotes the growth of bifidogenic bacteria and is efficiently fermented by gut microbes. Polydextrose is a soluble non-viscous manmade polymer that is only partially fermented by the gut microbiota.

An important factor drawing the attention of food manufactures to the use of polydextrose in various applications is its simplicity. Here the homogeneity of the compound may work to its advantage over grain fibres in certain applications. Since polydextrose is a synthetic compound, it’s not subject to the natural variations that may affect natural products. The taste, described as clean and non-sweet (vis the low calorie content) does not interfere with the flavor of the end product.

High solubility, clarity and rheological properties similar to sucrose make polydextrose versatile enough to add a desirable texture to a variety of liquids, including dairy drinks and yogurts, sauces and dressings, while reducing calories from fat or sugar. Consumers in general do not want to taste the fibre, but are attracted to smoother and richer consistency when it comes to various liquids. Taste and texture are always key concerns when reformulating foods to a health-conscious audience…..

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