Isomalto/Malto-Polysaccharide, A Novel Soluble Dietary Fiber Made Via Enzymatic Conversion of Starch

• Published in: Journal of agricultural and food chemistry Vol. 62; no. 49; pp. 12034 - 12044
• Main Authors: Leemhuis, Hans, Dobruchowska, Justyna M, Ebbelaar, Monique, Faber, Folkert, Buwalda, Pieter L, van der Maarel, Marc J. E. C, Kamerling, Johannis P, Dijkhuizen, Lubbert
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.12.2014; American Chemical Society, Books and Journals Division
• Subjects: 4,6-alpha-glucanotransferase; amylose content; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Biocatalysis; chain-length; dextranase; dextransucrase; dietary fiber; Dietary Fiber - analysis; Dietary Fiber - metabolism; Digestion; enzymes; glucose; Glycogen Debranching Enzyme System - chemistry; Glycogen Debranching Enzyme System - metabolism; health promotion; human health; Humans; in vitro studies; including resistant starch; ingredients; Lactobacillus reuteri; Lactobacillus reuteri - enzymology; lactobacillus-reuteri 121; large intestine; maltodextrins; Models, Biological; mouthfeel; oligosaccharides; Polysaccharides - chemistry; Polysaccharides - metabolism; prebiotics; Prebiotics - analysis; processed foods; small intestine; starch; Starch - chemistry; Starch - metabolism; structural-characterization; taste; texture; glucansucrase; α-glucan; isomalto-oligosaccharide; glucanotransferase; starch; prebiotic; dietary fiber; lactic acid bacteria
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf503970a

Dietary fibers are at the forefront of nutritional research because they positively contribute to human health. Much of our processed foods contain, however, only small quantities of dietary fiber, because their addition often negatively affects the taste, texture, and mouth feel. There is thus an urge for novel types of dietary fibers that do not cause unwanted sensory effects when applied as ingredient, while still positively contributing to the health of consumers. Here, we report the generation and characterization of a novel type of soluble dietary fiber with prebiotic properties, derived from starch via enzymatic modification, yielding isomalto/malto-polysaccharides (IMMPs), which consist of linear (α1 → 6)-glucan chains attached to the nonreducing ends of starch fragments. The applied Lactobacillus reuteri 121 GTFB 4,6-α-glucanotransferase enzyme synthesizes these molecules by transferring the nonreducing glucose moiety of an (α1 → 4)-glucan chain to the nonreducing end of another (α1 → 4)-α-glucan chain, forming an (α1 → 6)-glycosidic linkage. Once elongated in this way, the molecule becomes a better acceptor substrate and is then further elongated with (α1 → 6)-linked glucose residues in a linear way. Comparison of 30 starches, maltodextrins, and α-glucans of various botanical sources, demonstrated that substrates with long and linear (α1 → 4)-glucan chains deliver products with the highest percentage of (α1 → 6) linkages, up to 92%. In vitro experiments, serving as model of the digestive power of the gastrointestinal tract, revealed that the IMMPs, or more precisely the IMMP fraction rich in (α1 → 6) linkages, will largely pass the small intestine undigested and therefore end up in the large intestine. IMMPs are a novel type of dietary fiber that may have health promoting activity.