Thermostability variation in alleles of barley beta-amylase

Eglinton, J.; Langridge, Peter; Evans, D. E.

doi:10.1016/s0733-5210(98)90010-8

Cited by 121 publications

(103 citation statements)

References 23 publications

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“…For both β-amylase thermostability assays there was a small amount of overlap at the margin between the Sd1 and Sd2L types. The original β-amylase thermostability test was applied to the barley 7 . It is well known that the presence of sugars, proteins and other soluble components provide increased enzyme thermostability 2,3 , while more recently Henson et al 19 has provided evidence that higher mash solute concentrations improve fermentability by protecting thermolabile enzymes such as β-amylase.…”

Section: Resultsmentioning

confidence: 99%

“…The limit dextrinase thermostability test 16 and the β-amylase thermostability test 7 were adapted for use with the combined 8 × 12 microtitre plate based protocol for measuring the levels of α-amylase, total β-amylase and total limit dextrinase activity 9 . This modification enabled the efficient and streamlined assessment of the large numbers of samples likely to be analysed by barley breeding programs.…”

Section: Equationmentioning

confidence: 99%

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Refining the Prediction of Potential Malt Fermentability by Including an Assessment of Limit Dextrinase Thermostability and Additional Measures of Malt Modification, Using Two Different Methods for Multivariate Model Development

Evans

Dambergs

Ratkowsky

et al. 2010

Journal of the Institute of Brewing

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J. Inst. Brew. 116(1), 86-96, 2010Prediction of malt fermentability (apparent attenuation limit -AAL) by measurement of the diastatic power enzymes (DPE), α-amylase, total limit dextrinase, total β-amylase, β-amylase thermostability, and the Kolbach index (KI or free amino nitrogen -FAN) is superior to the conventional use of diastatic power (DP) alone. The thermostability of β-amylase is known to be an important factor in determining fermentability, thus the thermostability of the other relatively thermolabile enzyme, limit dextrinase, was investigated to determine if it was also useful in predicting fermentability. To facilitate this aim, methods were developed for a rapid and cost efficient assay of both β-amylase and limit dextrinase thermostability. Internationally important Australian and international malting varieties were compared for their total limit dextrinase and β-amylase activity and thermostability. Interestingly, the level of limit dextrinase thermostability was observed to be inversely correlated with total limit dextrinase activity. The prediction of malt fermentability was achieved by both forward step-wise multi-linear regression (MLR) and the partial least squares (PLS) multivariate model development methods. Both methods produced similar identifications of the parameters predicting wort fermentability at similar levels of predictive power. Both models were substantially better at predicting fermentability than the traditional use of DP on its own.The emphasis of this study was on the identification of predictive factors that can be consistently used in models to predict fermentability, because the model parameter estimates will subtly vary depending on mashing conditions, yeast strain/fermentation conditions and malt source. The application of these multivariate model development methods (PLS and MLR) enabled the identification of further potential fermentability predicting factors. The analyses divided the predictive parameters into those defined by DP enzymes and those associated with modification (KI, FAN, fine/coarse difference, wort β-glucan and friability). Surprisingly, limit dextrinase thermostability was not a substantial predictor of fermentability, presumably due to its negative correlation with total limit dextrinase activity. The application of these insights in the malting and brewing industries is expected to result in substantial improvements in brewing consistency and enable more specific quality targets for barley breeder's progeny selection cut-off limits to be more precisely defined.

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Section: Resultsmentioning

confidence: 99%

Section: Equationmentioning

confidence: 99%

Refining the Prediction of Potential Malt Fermentability by Including an Assessment of Limit Dextrinase Thermostability and Additional Measures of Malt Modification, Using Two Different Methods for Multivariate Model Development

Evans

Dambergs

Ratkowsky

et al. 2010

Journal of the Institute of Brewing

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“…Two major forms (Sd1 and Sd2) have been observed in commercial barley varieties. Sd2 was shown to have higher thermosablity, and a third form (Sd3) with increased thermostability was identified in Hordeum spontaneum (Eglinton et al 1998;Kihari et al 1998). This enzyme has been shown to remain active at temperatures >60°C under simulated commercial mashing conditions.…”

Section: Malt Qualitymentioning

confidence: 99%

Molecular basis of barley quality

Fox¹,

Panozzo²,

Li³

et al. 2003

Aust. J. Agric. Res.

163

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Abstract. The quality of barley for the range of end uses from animal feed to brewing is determined by many genes, making the breeding of new barley varieties difficult. Understanding of the molecular basis of barley quality has been advanced by biochemical studies. More recently, molecular genetic tools are allowing the analysis of the biochemical factors contributing to grain quality. Many genetic loci influencing key quality attributes have been identified by gene mapping. Limited success has been reported in using this information to select for quantitative trait loci for these quality traits in plant breeding. Genomic techniques allowing more detailed analysis of variations in the barley genome in relation to quality promise to extend significantly the value of molecular genetic approaches to barley quality improvement. Definition of the genetic basis of malting quality requires the identification of the genes involved in germination and endosperm modification. Feed quality remains difficult to define. Recent advances are likely to accelerate the rate of discovery, providing new options for analysis of barley quality.

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“…Alexis has been a leading variety in Germany and neighbouring countries since its release in 1986. Its key features include spring growth habit, semi-dwarf stature (sdw gene), mildew resistance (mlo allele), wide adaptation, long basic vegetative period (bvp), high malt extract, low wort viscosity, and good diastatic power (it carries the SD1 allele for β-amylase, Eglinton et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Sloop was bred by R. C. M. Lance, D. H. B. Sparrow, and A. R. Barr in South Australia and released in 1995. Sloop has many desirable features for malting including good diastatic power (SD1 allele for β-amylase, Eglinton et al 1998), low wort viscosity, very low wort β-glucan, moderately high fermentability, and good free amino nitrogen. However, its malt extract, although equal to the Australian industry standard Schooner, is lower than Alexis.…”

Section: Introductionmentioning

confidence: 99%

Mapping and QTL analysis of the barley population Alexis × Sloop

Barr¹,

Jefferies²,

Broughton³

et al. 2003

Aust. J. Agric. Res.

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Abstract. Two populations between the German malting variety Alexis and the Australian malting variety Sloop were constructed, mapped, phenotyped, and subjected to quantitative trait loci analysis. One population consisted of 153 F 4 -derived recombinant inbred lines and the other of 111 doubled haploid lines. This paper describes 18 field and laboratory experiments conducted with the populations and summarises the traits mapped and analysed. The genetic basis of 5 traits (malt extract, resistance to leaf rust, resistance to powdery mildew, early flowering, plant stature) important to Australian efforts to improve malting barley varieties was elucidated. Detailed maps for these populations are shown in this paper, while a consensus map incorporating these maps and further experiments on the populations are described elsewhere in this issue.

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Thermostability variation in alleles of barley beta-amylase

Cited by 121 publications

References 23 publications

Refining the Prediction of Potential Malt Fermentability by Including an Assessment of Limit Dextrinase Thermostability and Additional Measures of Malt Modification, Using Two Different Methods for Multivariate Model Development

Refining the Prediction of Potential Malt Fermentability by Including an Assessment of Limit Dextrinase Thermostability and Additional Measures of Malt Modification, Using Two Different Methods for Multivariate Model Development

Molecular basis of barley quality

Mapping and QTL analysis of the barley population Alexis × Sloop

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