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Carbohydrate quality of barley products with focus on β-glucan

Djurle, Susanne (2017). Carbohydrate quality of barley products with focus on β-glucan. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2017:46
ISBN 978-91-576-8865-1
eISBN 978-91-576-8866-8
[Doctoral thesis]

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Abstract

Barley (Hordeum vulgare L.) has a high content of dietary fibre and especially of mixed-linkage (1→3),(1→4)-β-D-glucan (β-glucan). It is well documented that a high intake of dietary fibre promotes beneficial health effects e.g. lower risk of type II diabetes and cardiovascular disease. β-Glucan in oats and barley even has an approved EFSA health claim for maintaining normal blood cholesterol levels. Cereals are usually processed before consumption and it is therefore important to study not only raw materials, but also how they are affected by processing.

Six barley varieties with different starch and dietary fibre content and composition were followed from kernel via sifted flour to two products: extruded breakfast cereal and bread. The starch and dietary fibre content and composition were analysed in each step to determine how processing affected each variety. The difference between kernels and sifted flour was large, as expected since the outer part of the kernel containing mostly insoluble dietary fibres was removed. The varieties were affected mostly in the same way and differences in kernels were observed also in sifted flours.

Extrusion increased the extractability of arabinoxylan and β-glucan while decreasing the molecular weights and the contents. The molecular weight of arabinoxylan of one variety (SW 28708) was less affected by extrusion than the other varieties while another variety (KVL 301) had a considerably lower extractability of β-glucan in the extruded product than the other varieties.

Bread baking also increased the extractability of β-glucan and arabinoxylan while decreasing the molecular weights. There was however one variety (SLU 7) that maintained a higher molecular weight of β-glucan. Since molecular weight reduction during baking is a known problem this was studied further. The β-glucanase activity was similar in sifted flour of all barley varieties, but higher for the wheat flour used in this study. This implied that differences in β-glucan breakdown depend on structure or some inhibitory factor in SLU 7. Incubation with water in 37 °C also gave lower breakdown of β-glucan in SLU 7 compared to other varieties. β-Glucan generally consists of 90% cellotriosyl and cellotetraosyl units but the ratio between them was different for SLU 7 than for other varieties, which could be part of the explanation for the differences in β-glucan breakdown.

Authors/Creators:Djurle, Susanne
Title:Carbohydrate quality of barley products with focus on β-glucan
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2017
Depositing date:20 April 2017
Volume:2017:46
Number of Pages:50
Papers/manuscripts:
NumberReferences
ISusanne Djurle, Annica A.M. Andersson, Roger Andersson (2016). Milling and extrusion of six barley varieties, effects on dietary fibre and starch content and composition. Journal of Cereal Science, 72, 146-152
IISusanne Djurle, Annica A.M. Andersson, Roger Andersson. Effects of bread baking on barley dietary fibre, with emphasis on β-glucan and resistant starch. (Submitted)
IIISusanne Djurle, Annica A.M. Andersson, Roger Andersson. β-Glucan resistance to degradation during bread baking. (Submitted)
IVElisa De Arcangelis, Susanne Djurle, Annica A.M. Andersson, Emanuele Marconi, Maria C. Messia, Roger Andersson. Structure analysis of β-glucan in six barley varieties differing in starch and dietary fibre composition. (Manuscript)
Place of Publication:Uppsala
Publisher:Department of Molecular Sciences, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8865-1
ISBN for electronic version:978-91-576-8866-8
ISSN:1652-6880
Language:English
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:barley, cereals, glucans, starch, baking, extrusion, dietary fibres, carbohydrates, carbohydrate metabolism, nutrition physiology
Keywords:barley, β-glucan, baking, extrusion, molecular weigth, dietary fibre, resistant starch
URN:NBN:urn:nbn:se:slu:epsilon-e-4117
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-4117
ID Code:14258
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Molecular Sciences
Deposited By: Susanne Djurle
Deposited On:21 Apr 2017 08:26
Metadata Last Modified:26 Jun 2017 00:40

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