Incorporation of Fibers in Foods: A Food Engineering Challenge

Abstract

Dietary fiber has been a focus of food industry research for some time now, owing to its importance in diet and the serious lack of fiber in commonly consumed foods. While the fortification of foods with fiber is, in theory, a simple way of increasing fiber consumption in the population, it is complicated by major engineering challenges. The incorporation of dietary fiber into processed foods often greatly compromises the texture and sensory quality of the food and also makes processing difficult. Physical, chemical, and enzymatic modifications of fiber have been investigated as strategies to improve its functionality. Modification strategies have mainly been aimed at changing the supramolecular and/or molecular structure of the fiber so as to improve its functionality. Several techniques for testing fibers for their functionality, including rheological tests such as solution rheology, lubricated squeezing flow, and capillary rheometry, are available. These techniques can be used to assess the quality of native or modified fibers and to predict their functionality under actual processing conditions. The macromolecular structure of fiber greatly affects its behavior during processing. Thus, a study of the structure of the fiber is complementary to the study of the rheological properties of the fiber, which can provide valuable information about its functionality. Some important structural characterization techniques include chemical analysis, spectroscopy techniques, and light-scattering techniques. Data regarding chemical modification of corn bran for incorporation into an extruded product, along with results of rheological and structural tests, are presented here to demonstrate the application of these techniques. The use of these modification strategies and fiber quality assessment techniques will help the food processor to formulate fiber-enriched products that will not hamper processing operations or the sensory quality of the product, while still imparting the health benefits associated with fiber consumption.