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Studies on starch structure and the differential properties of starch branching enzymes

Andersson, Lena (2001). Studies on starch structure and the differential properties of starch branching enzymes. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Agraria, 1401-6249 ; 287
ISBN 91-576-5834-X
[Doctoral thesis]

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Abstract

Starch is a staple food in human and animal diets, but also a raw material widely used for industrial purposes. By genetical modification of starch-synthesising enzymes in crop plants, starch yields could be increased and novel starches with particular qualities could be produced for industrial use. However, the process of starch biosynthesis and its regulation is still not completely understood. One of the major groups of enzymes in starch biosynthesis is the starch branching enzymes (SBEs), which introduce the branch points into amylopectin. This thesis describes some properties of two different families of SBEs from potato and barley. In addition, starch structure from both developing and mature barley has been characterised. Initially, a linear substrate for in vitro studies of SBEI and SBEII from potato was prepared. The linear dextrins were produced by enzymatic hyrdolysis of retrograded starch and then further fractionated through ethanol precipitation. The in vitro branching properties of SBEI and SBEII from potato were examined using iodine-staining, NMR spectroscopy, chromatographic and enzymatic methods. The two enzyme isoforms showed different substrate specificities and the branched products exhibited different chain length distribution profiles, but a similar degree of branching. In develping barley, starch structure and the expression of the gene encoding for barley SBEI were examined. The amylose content increased during development and followed a time course similar to that of the expression of the SBEI gene. The amylopectin chain length distribution was examined in the later stages of development, but no changes in the amylopectin structure were observed. In mature waxy barley, the amylose content and amylopectin structure in different parts of the grain were analysed. It was shown that the amylose content was signigicantly higher in the peripheral parts of the endosperm than in the centre, whereas the amylopectin chain length distribution was similar in all parts of the endosperm.

Authors/Creators:Andersson, Lena
Title:Studies on starch structure and the differential properties of starch branching enzymes
Year of publishing :July 2001
Volume:287
Number of Pages:36
Papers/manuscripts:
NumberReferences
ALLI. Andersson, L., Rydberg, U., Larsson, H., Andersson, R. and Åman, P. Preparation and characterisation of linear dextrins and their use as substrates in in vitro studies of starch branching enzymes. Accepted for publication in Carbohydrate Polymers. II. Rydberg, U., Andersson, L., Andersson, R., Åman, P. and Larsson, H. Comparison of starch branching enzyme I and II from potato. Submitted for publication. III. Andersson, L., Andersson, R., Andersson, R.E., Rydberg, U., Larsson, H. and Åman, P. Characterisation of the in vitro products of potato starch branching enzymes I and II. Submitted for publication. IV. Sathish, P., Sun, C., Ahlandsberg, S., Andersson, L., Åman, P. and Jansson, C. Characterization of a cDNA encoding starch branching enzyme I in barley. Submitted for publication. V. Andersson, L., Fredriksson, H., Oscarsson Bergh, M., Andersson, R., and Åman, P. 1999. Characterization of starch from inner and peripheral parts of normal and waxy barley kernels. Journal of Cereal Science, 30, 165-171.
Place of Publication:Uppsala
ISBN for printed version:91-576-5834-X
ISSN:1401-6249
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F60 Plant physiology and biochemistry
Q Food science > Q04 Food composition
Subjects:Not in use, please see Agris categories
Agrovoc terms:starch, chemical composition, food technology, enzymes, starch crops, potato starch, barley
Keywords:barley, potato, amylose, amylopectin, Hordeum vulgare L., Solanum tuberosum L., starch branching enzyme, starch biosynthesis
ID Code:312
Department:(NL, NJ) > Dept. of Food Science (until 161231)
Deposited By: Staff Epsilon
Deposited On:28 Jul 2003 00:00
Metadata Last Modified:02 Dec 2014 10:03

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