Food scientist’s guide to dietary fiber

Abstract

In the past 50 years or so dietary fiber has become an increasingly significant area of nutritional focus, debate, and research. Advances in food production practices have resulted in more and more refined foods being available and consumed throughout the world and particularly in developed nations such as the United States. While refined foods are typically more palatable to consumers, the content of dietary fiber is greatly reduced. Currently many diseases are believed to be associated with a lack of dietary fiber intake, and furthermore significant health benefits are thought possible via increased consumption of many dietary fibers. These issues are discussed in Chapter 2- Dietary Fiber and Disease. There is not a well accepted definition for dietary fiber, but most reference the human inability to fully digest fibers, fibers being made up of various monomer units of variable length, and some mention plant origin. In many ways the definition of dietary fiber is connected to the analytical methods used to quantify it, which there are many, several of which are detailed in Chapter 5- Analytical Techniques for Dietary Fiber. Newer ingredients that are not quantified by typical fiber analysis methods have created the need for additional assays. Dietary fiber is subject to all sorts of labeling regulations and a few nutritional claims. This has resulted in many manufacturers taking an interest in increasing the fiber content of their products while maintaining product quality and label friendliness. There are many raw materials/ingredients that can increase the fiber content in foods, each with its own set of functional and sensory characteristics. These are detailed in Chapter 7 and include acacia gum, beta glucan, cellulose, chitin/chitosan, corn bran, corn fiber, inulin, oat Bran/oat fiber, pea fiber, pectin, polydextrose, psyllium, resistant starch, rice bran, soy fibers, wheat bran, and wheat fiber. These fibers are unique in their functional capability and effect on flavor and texture. Discussion of the product development considerations includes these functional characteristics as well as cost, ingredient labeling requirements, usage levels, other sensory characteristics, storage stability, and effect on water activity.