Research and Application Prospects of Novel Water-Soluble Fibers: Dextran and Natural Plant Gum

Otsuka Pharmaceutical, a major manufacturer of sports drinks and other beverages, has developed a variety of popular drinks. "FIBEMINI" is one of them. Drinking "FIBEMINI" has a fashionable appeal to young women, making it a popular beverage. The main ingredient in this popular drink is dextran, a low-energy food ingredient developed by an American pharmaceutical company. Dextran cannot be broken down by enzymes that break down sugars, such as amylase; however, a very small portion can be broken down by intestinal bacteria, and only this small portion can be absorbed and converted into energy.

Therefore, its calorie content is only one-quarter that of sugars such as starch and sucrose, which can be broken down by digestive enzymes, making it a low-energy, water-soluble dietary fiber with 1 kcal per gram. Glucan is a non-product synthesized by heating a mixture of glucose and sorbitol in a 9:1 ratio with a small amount of citric acid. The U.S. Food and Drug Administration (FDA) reviewed experimental data on the acute toxicity, subacute toxicity, carcinogenicity, teratogenicity, and mutagenicity of glucan and concluded that it has a high safety profile. Due to its favorable properties as a dietary fiber, it can be used as a food ingredient once approved.

In June 1983, Japan approved dextran as a food product. Previously, it was approved as a chemically synthesized food additive. Unlike other natural water-soluble dietary fibers such as pectin in fruits, mannan in konjac, and alginic acid in seaweed, which become sticky and unpleasant when dissolved in water, dextran dissolves in a refreshing liquid and can be used in beverages. The success of dextran inspired many manufacturers to develop natural water-soluble dietary fibers. Yongnian Company developed xanthan gum, guar gum, tamarind seed polysaccharides, and pectin, while Dai Nippon Pharmaceutical Company developed a "plant gum" based on galactomannan polysaccharides.

Guar gum is a natural high-molecular-weight polysaccharide extracted from guar beans, a plant native to India and Pakistan. It has very strong viscosity. By hydrolyzing it into molecules of appropriate size using an enzyme isolated from microorganisms, and then dissolving it in cold water, its viscosity is greatly reduced. This substance is not broken down by human digestive enzymes, and its aqueous solution is neutral, colorless, transparent, tasteless, and odorless, without affecting the texture, and can be added to any food. In addition, a dietary fiber beverage called "Fiber Lemon," which contains natural galactomannan polysaccharide-based water-soluble dietary fiber "plant gum," is already on the market.

In India, there is a cultivated plant in the Plantaginaceae family. The outer shell of the seeds of this plant contains natural plant gum, which can absorb a large amount of water to form a highly viscous dispersion, and has therefore been used as a laxative since ancient times. A Japanese company has used this natural plant gum to produce a dietary fiber product (brand name "Mermaid Fiber") in 3-gram packets, which is sold on the market. Simply dissolve it in water or a beverage and drink it to conveniently supplement dietary fiber.