title: Time-resolved in-situ observation of starch polysaccharide degradation pathways.
abstract: Analytical challenges in the direct time-resolved observation of starch metabolism have been addressed by using optimized multidimensional NMR experiments. Starch provides the main source of human dietary energy intake and is a raw material for beverage and renewable fuel production. Use of direct in situ observations of starch remodeling pathways could facilitate our understanding and control of processes of biotechnological, medical, and environmental relevance. Processes involving starch synthesis or degradation are difficult to monitor directly in aqueous solution, however, because starch consists of glucopyranosyl homopolymers that are built up from and degraded into structurally similar fragments that yield only small signal dispersion in optical and NMR spectroscopy. By focusing on acetal groups only, (1) H,(13) C HSQC experiments sampling narrow spectral windows in the highly resolved (13) C dimension have been employed in order to observe the amylopectin cleavage pathway in real time with a temporal resolution of 150 s. Quantifiable signals for more than 15 molecular species emerging during starch fragmentation by human saliva have been resolved and tracked over time in this manner. Altered accumulation of intermediates in the digestion of amylopectin in the presence of black tea acting as an effector have been monitored.
authors.affiliation: Carlsberg Laboratory, Gamle Carlsberg Vej 10, 1799 Copenhagen V (Denmark).
authors.forename: Sophie R
authors.initials: SR
authors.lastname: Beeren
authors.forename: Bent O
authors.initials: BO
authors.lastname: Petersen
authors.forename: Marie
authors.initials: M
authors.lastname: Bøjstrup
authors.forename: Ole
authors.initials: O
authors.lastname: Hindsgaul
authors.forename: Sebastian
authors.initials: S
authors.lastname: Meier
mesh_terms: D000687:Amylopectin / Q000032:analysis / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011134:Polysaccharides / Q000032:analysis / Q000378:metabolism*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism*; D013213:Starch / Q000032:analysis / Q000378:metabolism
chemical_list: D011134:Polysaccharides; D013213:Starch; D000687:Amylopectin
keywords: NMR spectroscopy; amylases; carbohydrates; pathway intermediates; starch metabolism