Fabricating low glycaemic index foods: Enlightened by the impacts of soluble dietary fibre on starch digestibility

Diabetes mellitus, which is one of the most prevalent chronic diseases, is a major cause of the increase in morbidity and mortality in humans. To relieve hyperglycaemia in diabetic patients, the control of blood glucose levels through the use of a low glycaemic index diet is highly recommended. In view of the predominant contribution of dietary starch to blood glucose, low starch digestibility foods can certainly benefit diabetic patients. Hence, food technologists have attempted to design foods with lowered starch digestibility by using various strategies, and the application of soluble dietary fibre (SDF) has attracted a considerable amount of attention. This work aimed to present an updated overview of the evidence, factors, and possible mechanisms of the impacts of SDF on starch digestibility. First, the in vitro , in vivo , and clinical evidence of SDF on starch digestibility was summarized. The SDF-starch digestibility relationship was found to be dependent on the nature of SDF and starch. The former factor included the type, application dose, charge, and molecular weight, and the latter mainly involved the type and physical state. Additionally, the mechanism underlying these concepts was explored, and it was found that SDF functions as follows: 1) the modification of the multiscale structure of starch or the involved food; 2) an increase in the viscosity of intestinal contents; 3) decreases in the activities of amylolytic enzymes; and 4) the regulation of the levels of hormones or other metabolites related to starch digestion. Finally, the perspectives and directions of future efforts were proposed in pursuing a full understanding of the underlying mechanism and more valuable data for designing healthy foods. • In vitro , in vivo and clinical evidence of SDF on starch digestibility was summarized. • Power of SDF on starch digestibility was jointly affected by SDF and starch nature. • The possible mechanisms to effects of SDF on starch digestibility were specified. • Prospects to design low glycemic index foods by SDF incorporation were proposed.