Non-Starchy Polysaccharides of Cereal Grains I. Fractionation of the Barley Gums

The effect of rain on the viscosity of an acid flour extract and on the acid-soluble, acid-insoluble and total ~-glucan contents of barley flour has been investigated. Four commercial varieties and two high lysine genotypes were studied. In the commercial varieties rain induces a decrease in the viscosity of the acid flour extract which is paralleled by decreases in soluble and total ~-glucan contents. Furthermore, it is concluded that the rain did not alter the structural nature of the acid-soluble ~,-glucans. The genotype having the lys-3a allele is characterized by such a low extract viscosity and ~-glucan content that the rain had no effect on these parameters. The rain had a very unexpected effect on the genotype having the lys allele, namely, a marked decrease in extract viscosity that was not accompanied by a decrease in ~-glucan contents. Similar analyses on pure endosperm demonstrated that the rain effect is not a result of an altered 1000-grain weight. In addition, the extract viscosity and the soluble I~-glucan content were found to decrease from yellow to full ripeness.

Section: Introductionmentioning

confidence: 99%

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

Aastrup

1979

“…Barley 13-glucan, prepared according to the method of PREECE and MCKENZIE (24), was a gift from Mrs. E. MEILING and J. A. SORENSEN M.sc., Department of Brewing Chemistry, Carlsberg Research Laboratory.…”

Section: Methodsmentioning

confidence: 99%

Immobilization of β-glucanase and studies on its degradation of barley β-glucan

Svensson

Ottesen

1978

A commercial fungal 13-glucanase preparation was immobilized by various methods including adsorption to DEAE-cellulose, cross-linking with glutaraldehyde, adsorption to a phenol-formaldehyde resin (Duolite) and to perlite followed by fixation with glutaraldehyde, covalent binding to glutaraldehyde-treated, partially hydrolyzed or partially aminolyzed nylon, and covalent binding in the Ugi-reaction to polyisonitrile-nylon. The recovery of enzymatic activity varied from 0.02 to 4.5% and the immobilized enzyme preparations showed specific activities from 1 to 25% of that of the starting material. DEAE-cellulose-, nylon-and Duolite-13-glucanase were used in packed bed reactors for continuous hydrolysis of barley 13-glucan. The Duolite-13-glucanase was most active in depolymerizing this polysaccharide. The action pattern of insoluble crude 13-glucanase (Duolite-13-glucanase) on barley 13-glucan was very different from that of the crude enzyme preparation in solution. Comparison with the mode of action of a homogeneous preparation of endo-l,4-13-glucanase in dissolved and immobilized form, respectively, indicated that this change in action pattern was partly due to coimmobilization of enzymes catalyzing consecutive steps in the hydrolysis of barley 13-glucan to glucose and partly to steric hindrance of the interaction between the immobilized enzyme and the interior regions of the substrate.

“…Denmark II 2 Sweden II 3 Denmark IV 4 W. Germany II c 5 Denmark III 6 II 7 IV 8 Holland II 9 Denmark I 10 Canada I 11 Malawi IV 12 Denmark I (12) modified by ERDAL and GJERTSEN (5) was used for the estimation of soluble [3-glucan in beer and wort. The [3-glucans were precipitated by 30g (NH4)2SO4 per 100 ml beer or wort at 0 ~ for l hour, centrifuged, and washed twice with 20% ethanol.…”

Section: Storage Of Beer and Wort Samplesmentioning

confidence: 99%

“…Traditionally the quantity of ~-glucans in wort and beer are estimated by precipitation with ammoniumsulphate (5,12), but analogous methods have been described using CuSO4 (11) or cold ethanol (3) for precipitation. These procedures, involving selective precipitation, purification, acid hydrolysis and determination of released glucose, are laborious and time consuming and are not suitable as a routine analysis in a brewery.…”

Section: Introductionmentioning

confidence: 99%

An improved method for determining β-glucan in wort and beer by use of Calcofluor

Jørgensen

1983

An improved method for the determination of~glucan in beer and wort employing the fluorochmme Calcofluor is described. Dimethylsulfoxid (20~ (v/v)) was used to obtain a reproducible binding ratio of Calcofluor to I}-glucan. The formed complex was precipitated by 77% ethanol and separated by centrifugation. The precipitate was dissolved in a glycine/NaOH buffer at pH ~ 10.0 and fluorescence was measured in a spectrofluorometer. The method correlates well with the established ammoniumsulphate precipitation method for ~-glucan for a wide range of beer and wort samples. Treatment of beers and worts with pure ~-glucanase gave a low background fluorescence, thus indicating a high specificity of the method. From dialysis experiments it was found that low molecular [3-glucans < 10,000 daltons only gave a slight binding to Calcofluor. The analysis is suitable for routine control in a brewery, allowing an output of at least 50 samples per day per person.