title: Particulate structure of phytoglycogen studied using β-amylolysis.
abstract: Phytoglycogen (PG), a dendrimer-like glucan particulate, has a much higher dispersed molecular density than amylopectin (AP). In this study, β-amylase was used to investigate the effect of high molecular density of PG on its susceptibility to enzymatic hydrolysis. AP and PG reached the limit of β-amylolysis at 20 and 480 min, respectively, suggesting a much higher resistance of PG to β-amylase. The majority of PG β-amylolysis occurred in the initial 2 min, followed by a slow progression that implied low accessibility of internal particulate portion to enzyme. The chain length profile of PG β-limit dextrin showed only one population of long chains, indicating the absence of branch clusters with PG. At the limit of β-amylolysis, a substantial decrease in the molar mass was observed for both PG and AP, whereas only a slight reduction in the Z-average root mean square radius was observed for PG (from 24.5 to 23.1 nm) compared to that of AP (from 91.1 to 69.6 nm).
authors.affiliation: Department of Food Science, Purdue University, United States.
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Agricultural & Biological Engineering, Purdue University, United States.
authors.forename: Ganesan
authors.initials: G
authors.lastname: Narsimhan
authors.affiliation: Department of Food Science, Purdue University, United States. Electronic address: yao1@purdue.edu.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
mesh_terms: D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005936:Glucans / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D008320:Maltose / Q000032:analysis / Q000302:isolation & purification; D008970:Molecular Weight; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism; D001614:beta-Amylase / Q000378:metabolism*; D047392:beta-Cyclodextrins / Q000032:analysis / Q000737:chemistry
chemical_list: D005936:Glucans; D047392:beta-Cyclodextrins; D008320:Maltose; D001614:beta-Amylase; C031215:betadex
keywords: Beta-amylolysis; Particulate structure; Phytoglycogen; Steric hindrance