New insights suggest isomaltooligosaccharides are slowly digestible carbohydrates, rather than dietary fibers, at constitutive mammalian α-glucosidase levels. (30th July 2022)

• Record Type: Journal Article
• Authors: Song, Young-Bo; Lamothe, Lisa M.; Esmeralda Nava Rodriguez, Nardo; Rose, David R.; Lee, Byung-Hoo
• Is Part Of: Food chemistry. Volume 383(2022)
• Publication Date: 2022-07-30
• Subjects: Isomaltooligosaccharides -- Dietary fiber -- Mammalian α-glucosidases -- Slowly digestible carbohydrates -- Glucose generation rate; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2022.132456
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Isomaltooligosaccharides (IMOs) were slowly hydrolyzed by mammalian α-glucosidases. Fungal amyloglucosidase (AMG) has a limitation to digest the isomaltose to glucose. IMOs can be misjudged as prebiotic ingredient by in vitro assay with AMG. IMOs can be applied as a slowly digestible ingredient instead of dietary fibers. IMOs have a potential to attenuate the post-prandial glycemic response. Abstract: Isomaltooligosaccharides (IMOs) have been characterized as dietary fibers that resist digestion in the small intestine; however, previous studies suggested that various α-glycosidic linkages in IMOs were hydrolyzed by mammalian α-glucosidases. This study investigated the hydrolysis of IMOs by small intestinal α-glucosidases from rat and human recombinant sucrase–isomaltase complex compared to commonly used fungal amyloglucosidase (AMG) in vitro . Interestingly, mammalian α-glucosidases fully hydrolyzed various IMOs to glucose at a slow rate compared with linear maltooligosaccharides, whereas AMG could not fully hydrolyze IMOs because of its very low hydrolytic activity on α-1, 6 linkages. This suggests that IMOs have been misjudged as prebiotic ingredients that bypass the small intestine due to the nature of the assay used. Instead, IMOs can be applied in the food industry as slowly digestible materials to regulate the glycemic response and energy delivery in the mammalian digestive system, rather than as dietary fibers.