Extraction methods of dietary fiber and effect on bioactivity: A review

A large number of food processing by-products are consumed every day that are not utilized and are rich in highly active nutrients: dietary fiber (DF). DF has been defined by nutritionists as the seventh macronutrient with many benefits to our health, such as improving intestinal flora, reducing obesity and lowering cardiovascular morbidity. Thus, suitable extraction methods are needed to obtain high yields of high and quality DFs (including the soluble dietary fiber and insoluble dietary fiber). DF extraction methods have received increasing attention because it is effective in improving the structure and functional properties of DF. However, to the best of our knowledge, no study has systematically analyzed and summarized the differences in different DF extraction methods and their exert on DF composition, structure and functional activities. In this paper, the extraction methods (physical method, chemical method, biological method and combined method) for DF which have been explored by researchers in the last decade are reviewed, and the effects caused by different extraction methods on the structure and functional activity of DF from different sources are summarized. Moreover, the mechanism, comparative analysis and future trends of different extraction methods for DF are discussed. This review will greatly promote the development and utilization of plant and by-product resources in China, and provide a theoretical basis for the demand of high-quality DFs for our people. Meanwhile, this review can provide theoretical guidance for selecting suitable DF extraction methods and achieving better industrialization of extracted DF.