Extraction and Modification of Dietary Fiber Applying Thermal Processes

This chapter describes the application of thermal treatments for the extraction and modification of dietary fiber (DF). In the last decades, the food industry has focused its attention on developing innovative food ingredients capable of providing health benefits without compromising their safety and technological functionality. The inclusion of DFs in the formulation of foods providing health benefits is of consumer and industry interest. Thermal processes, without the use of chemical reagents, have been widely utilized for the extraction and modification of DFs. Hot and boiling water, scalding, blanching, steam explosion, and thermal extrusion have been used to extract DFs, and to modify DF fractions and components. DF extraction at elevated temperatures results in higher extraction yields, particularly of highly insoluble compounds. Thermal treatments can also modify the composition of DFs by solubilizing their insoluble fraction. This modification has the potential of improving their functionality. Additional thermal treatment used as a final conditioning step of previously extracted and modified DF products, such as hot air-drying, have also been proven to further modify DFs.