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Stabilization of semi-solid-state starch by branching enzyme-assisted chain-transfer catalysis at extreme substrate concentration

Paper ID Volume ID Publish Year Pages File Format Full-Text
3361 166 2013 10 PDF Available
Title
Stabilization of semi-solid-state starch by branching enzyme-assisted chain-transfer catalysis at extreme substrate concentration
Abstract

In this study a branching enzyme (BE, α-1,4 → α-1,6 glycosyltransferase) was used to modify starch granules of different structures at high temperature and at extreme starch dry matter content (30–40%, w/v) to restrict temperature-induced swelling. As opposed to diluted systems, such conditions led to stabilization of the granular structure for low-phosphate starch types at the highest BE activity. Bright field/polarized light and scanning electron microscopy confirmed maintenance of granular structure. The product compared to the control had significantly increased degree of branching as identified by shorter branch-length of the α-1,4 chains assessed by chromatography and larger proportion of α-1,6 links to α-1,4 links as assessed by 1H nuclear magnetic resonance spectroscopy. Size exclusion chromatography demonstrated the presence of uniform molecules with smaller size. Further the polysaccharide product was 40% more soluble at 25 °C than the corresponding heat treated control. Both of these observations were supported by 13C solid-state MAS NMR. Hence, significant chain transfer took place in the semi-solid state starch permitting conservation of the main granular organization in the final product. A hypothetic model is presented to account for the observed phenomenon.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A branching enzyme was used to modify thermally partially opened starch granules. ► Highly branched, molecularly uniform and cross-linked granular starch was generated. ► A new concept for enzyme-assisted modification of compact polysaccharides is provided.

Keywords
AP, amylopectin; AM, amylose; BE, branching enzyme; BEU, branching enzyme unit; CBM, carbohydrate binding module; CP, cross polarization; DM, dry matter; GWD, glucan water dikinase; HPAEC-PAD, high performance anion exchange chromatography with pulsed amp
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Stabilization of semi-solid-state starch by branching enzyme-assisted chain-transfer catalysis at extreme substrate concentration
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 72, 15 March 2013, Pages 1–10
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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