Production of highly branched alpha-limit dextrins with enhanced slow digestibility by various glycogen-branching enzymes

Abstract

alpha-Limit dextrins (alpha-LDx) are slowly digestible carbohydrates that attenuate postprandial glycemic response and trigger the secretion of satiety-related hormones. In this study, more highly branched alpha-LDx were enzymatically synthesized to enhance the slowly digestible property by various origins of glycogen branching enzyme (GBE), which catalyzes the transglycosylation to form alpha-1,6 branching points after cleaving alpha-1,4 linkages. Results showed that the proportion of branched alpha-LDx in starch molecules increased around 2.2-8.1 % compared to alpha-LDx from starch without GBE treatment as the ratio of alpha-1,6 linkages increased after different types of GBE treatments. Furthermore, the enzymatic increment of branching points enhanced the slowly digestible properties of alpha-LDx at the mammalian alpha-glucosidase level by 17.3-28.5 %, although the rates of glucose generation were different depending on the source of GBE treatment. Thus, the highly branched alpha-LDx with a higher amount of alpha-1,6 linkages and a higher molecular weight can be applied as a functional ingredient to deliver glucose throughout the entire small intestine without a glycemic spike which has the potential to control metabolic diseases such as obesity and type 2 diabetes.