The relationship between the viscosity of an acid flour extract of barley and its β-glucan content

Abstract

The relationship between the viscosity of an acid flour extract and the acid-soluble, acid-insoluble and total [~-glucan content of barley flour has been investigated. The extract viscosity was found to be closely related (R2 = 0.99, S.E.E. = 0.19) to the content of soluble ~,-glucan. It is concluded that the acid-soluble [~-glucans from 14 of the 18 different genotypes studied have a similar structural nature. Genotypes containing the lys-3a allele were found to have very low extract viscosities and [~-glucan contents. Quick and accurate methods are described for measuring viscosities of acid extracts made from flour derived from grains of a single plant and flour derived from a single grain. These methods can be used to screen plants for their soluble (3-glucan content in a plant breeding program.

Quantitative determination of endosperm modification and its relationship to the content of 1,3∶1,4-β-glucans during malting of barley

“…Simple tests such as the viscosity of acid flour extract (1,15,18), milling energy (3) and barley flour sedimentation value (20) have been previously employed. However, one of the most important properties of a good malting barley is a rapid and even germination, which can neither be measured by classical malt analyses nor by barley tests.…”

“…The lot of 1,3:l,4-t~-glucan 4-endo-hydrolase used in the present study has been previously described (1). The [~-glucan content was calculated as glucose equivalents and all results represent the mean of triplicate determinations.…”

The effect of rain on β-glucan content in barley grains

“…It is a general observation that a wet harvest results in barley grains whose flour is characterized by a low extract viscosity and ~-glucan content, while a dry harvest yields grains whose flour has a high extract viscosity and ~-glucan content. Therefore, possible relationships between barley extract viscosities and ~-glucan contents have often been discussed (see 1). Such a correlation has now in fact been demonstrated (i).…”

Selection and characterization of low β-glucan mutants from barley

“…This may be due to the warmer and drier S. AASTRUP: LOW I~-glucan barley mutants (17) and higher levels of total 13-glucan content. Very low viscosities of the acid extracts are seen for all the selected lines, which implies that they have very little acid soluble fS-glucan (2,29). The low viscosities are paralleled by large decreases in total 13-glucan content for the mutants M-737 and M-1460 compared with Minerva, while M-699 and M-892 show a smaller decrease.…”

“…Extraction of flour with HCI solution (pH 1.5) and the determination of extract viscosity were carried out as previously described (2) except that the ratio of flour to acid solution was increased from 0.2 g flour/2 ml to 0.3 g flour/2 ml.…”