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Barley starch

molecular structure and properties

Källman, Anna (2013). Barley starch. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2013:73
ISBN 978-91-576-7884-3
eISBN 978-91-576-7885-0
[Doctoral thesis]

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This thesis examined barley amylopectin structure and looked for correlations between the structure and physical properties of starch. The structure of amylopectin and gelatinisation and retrogradation of starch were studied in 10 different barley cultivars/breeding lines with differing genetic background.

Amylopectin is built up of thousands of chains of glucose monomers, organised into clusters. The detailed fine structure of amylopectin was studied by isolating clusters of amylopectin and their building blocks, which are the tightly branched units building up the clusters. Barley cultivars/breeding lines possessing the amo1 mutation had fewer long chains of DP≥38 in amylopectin and more large building blocks. The structure of building blocks was rather conserved between the different barley cultivars/breeding lines studied and was categorized into different size groups. These different building blocks were shown to be randomly distributed in the amylopectin molecule. The C-chains in amylopectin can be of any length and are a category of chains different from the B-chains. The backbone in amylopectin consists of a special type of B-chains which, when cleaved by α-amylase, become chains of a similar type to C-chains.

Gelatinisation and retrogradation (recrystallisation of gelatinised starch) of barley starch was studied by differential scanning calorimetry. The amo1 mutation resulted in a broader gelatinisation temperature range and a higher enthalpy of retrogradation. Other structural features were also found to influence the physical properties of starch. Small clusters and denser structure of the building blocks resulted in higher gelatinisation temperature. Fast retrogradation was observed in barley which had amylopectin with shorter chains and many large building blocks consisting of many chains.

Amylopectin structure was also studied in developing barley kernels. Three barley cultivars/breeding lines were grown in a phytotron and kernels were harvested at 9, 12 and 24 days after flowering. The results showed that amylopectin synthesized at later stages of development had a more tightly branched structure. Expression of the enzymes involved in starch biosynthesis is also known to change during endosperm development.

Authors/Creators:Källman, Anna
Title:Barley starch
Subtitle:molecular structure and properties
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :October 2013
Number of Pages:56
IBertoft, E., Källman, A., Koch, K., Andersson, R., Åman, P. (2011). The cluster structure of barley amylopectins of different genetic backgrounds. International Journal of Biological Macromolecules 49(4), 441-453.
IIBertoft, E., Källman, A., Koch, K., Andersson, R., Åman, P. (2011). The building block structure of barley amylopectin. International Journal of Biological Macromolecules 49(5), 900-909.
IIIKällman, A., Bertoft, E., Koch, K., Åman, P., Andersson, R. (2013). On the interconnection of clusters and building blocks in barley amylopectin. International Journal of Biological Macromolecules 55, 75-82.
IVKällman, A., Vamadevan, V., Bertoft, E., Koch, K., Seetharaman, K., Åman, P., Andersson, R. Starch structure, gelatinization and retrogradation properties in barley samples with a high variation in carbohydrate composition (manuscript).
VKällman, A., Sun, C., Koch, K., Åman, P., Andersson, R. Starch structure in developing barley endosperm (manuscript).
Place of Publication:Uppsala
Publisher:Dept. of Food Science, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7884-3
ISBN for electronic version:978-91-576-7885-0
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:Q Food science > Q01 Food science and technology
Q Food science > Q04 Food composition
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Food Science
Agrovoc terms:hordeum vulgare, barley, starch, amylopectin, chemical structure, chemicophysical properties, jellification, biosynthesis, varieties, mutation
Keywords:barley, starch, amylopectin fine structure, clusters, building blocks, C-chain, gelatinisation, retrogradation
Permanent URL:
ID Code:10845
Faculty:NL - Faculty of Natural Resources and Agricultural Sciences (until 2013)
Department:(NL, NJ) > Dept. of Food Science (until 161231)
Deposited By: Anna Källman
Deposited On:09 Oct 2013 13:56
Metadata Last Modified:27 Sep 2016 07:39

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