Enzymatic Modification of Dietary Fiber Sources

Abstract

It is generally agreed that an increase in dietary fiber consumption in western countries would be beneficial to maintaining health. The average fiber intake in Europe has been reported to be in the range of 16–21 g/day (1). Highly variable values are found for Japan [12–24 g/day (2)], whereas in the United States the daily intake is even lower [12–13 g/day (3)]. To reach the recommendations of 20–35 g of dietary fiber per day, or 10–12 g/1000 kcal, it would be necessary to change dietary habits by increasing the intake of fruits, vegetables, and whole grain cereal products. Another possibility is the production of fiber-enriched foods incorporating dietary fiber sources such as cereal brans, pulps, or pomaces, which are mainly used as feed, fertilizers, or fuels (4,5). However, due to their physicochemical properties, which can cause severe functional problems in product development, most of these by-products cannot be added in physiologically relevant amounts. In addition, off-flavors and unpleasant color and texture make incorporation difficult. One way to overcome these technological and organoleptic problems is enzymatic modification. In this chapter procedures to modify dietary fiber sources by means of enzyme preparations are reviewed. Two different approaches are possible. On the one hand, an increase in dietary fiber content can be achieved by removing digestible compounds. On the other hand, chemical composition as well as physicochemical properties can be altered by enzyme attack of the fiber fraction itself.