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Predicting Fermentability from DP Enzyme Levels

Predicting Fermentability from DP Enzyme Levels. Dr Evan Evans Tasmanian Institute of Agricultural Research University of Tasmania Australia. Australian Barley Biochemistry & Brewing Research Barley Malting Quality … from Grass to Glass. Introduction: Evan Evans. Interests

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Predicting Fermentability from DP Enzyme Levels

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  1. Predicting Fermentability from DP Enzyme Levels Dr Evan Evans Tasmanian Institute of Agricultural Research University of Tasmania Australia Australian Barley Biochemistry & Brewing Research Barley Malting Quality … from Grass to Glass.

  2. Introduction: Evan Evans • Interests • Research into improving malt quality for brewing •  malt proteins & components that influence beer foam & haze • malt components that influence mash/beer filtration • malt proteins that produce fermentable sugars from starch • microbial assurance and quality of barley and malt •  malt enzymes that influence beer flavour stability •  Joined the University of Tasmania in 2002 •  Worked with SA Barley Improvement program 1992-2002 •  select for barley with improved malting quality • Overall aim: make better quality beer and more of it!

  3. Barley Production Areas Barley Growing Areas Barley Improvement Centres Germplasm Improvement Queensland Western Australia Grimmett Lindwell Tallon Fitzroy South Australia New South Wales Victoria Stirling Gairdner Vlamingh Baudin Hamelin Schooner Sloop Gairdner Buloke Flagship Baudin Schooner Sloop Gairdner Flagship Baudin Tasmania

  4. Introduction Beer is produced by the yeast mediated conversion of fermentable sugars into alcohol. Fermentable sugars are released from starch by the diastatic power enzymes during mashing.

  5. Starch is degraded by the four diastase enzymes

  6. Starch degradation is a balance between: • Starch gelatinization - temps > 60°C • DP enzyme thermal inactivation < 65°C • “degradation window of opportunity”

  7. Thermostability characteristics of DP enzymes: • b-amylase: activity remaining 60oC for 10minSd2L ~ 3%, Sd1 ~ 10%, Sd2H ~ 25% • Limit dextrinase: activity rem. 57.5oC for 15minrange 18% to 85% • a-amylase: activity remaining 72.5oC for 10minrange 9% to 63% • a-glucosidase: ?

  8. 120 40 100 30 80 20 60 10 40 0 Relationship between b-amylase thermostability and wort fermentability in 42 commercial samples( Extracted from Eglinton et al., 1998) Sd1 Sd1 Sd2-H Sd2-H Sd2-L Sd2-L Residual b-amylase Actvity (%) DP (oL) 2 % point AAL advantage for Sd2H varieties 76 78 80 82 78 80 82 84 Fermentability (AAL %) Fermentability (AAL%)

  9. Mash Temperature Programming 50min 10min 15min Add 100ml water Degradation window of opportunity Attemperation

  10. 5.7% The influence of mash in temperature on AAL and sugar composition

  11. Predicting AAL from malt characteristics Evans et al., 2005, J. Am. Soc. Brew. Chem. 63:185-198 AAL = 69.9 + 0.017*a + 9.60*b + 0.195*c + 0.007*d + 0.538e - 0.001*d*e r2 = 0.91 Parameters DP Enzyme MLR (multi linear regression): a = a-Amylase activity, b = Total limit dextrinase activity c = KI (%) d = Total b-amylase activity e = b-Amylase thermostability (%) DP enzymes measured with Megazyme substrates

  12. Biochemical meaning of parameters? • Parameters: • a-Amylase:Primary starch attack to produce substrates for b-amylase and limit dextrinase. • Limit dextrinase:a-1,6-glycosidic bond cleavage to produce fermentable sugars and substrates for b-amylase. • b-Amylase activity:determinant of maltose production. • b-Amylase thermostability:maintain b-amylase activity (ie new Sd2H variety Flagship). • KI (%):access of enzymes to starch.

  13. Aims: • Better predict malt fermentability performance. • Is the DP malt quality parameter useful? • Investigate variation in levels of DP enzymes. • Evaluate and validate concept of testing of DP enzymes • Improved malt selection by maltsters, brewers & breeders

  14. Validation of measurement Of DP enzymes

  15. Prediction (r2) between DP enzymes and PBA data 2004 (n=11)

  16. Prediction (r2) between DP enzymes and PBA data 2005 (n=10)

  17. Application of DP enzyme testing: Commercial malt production

  18. Variation of DP enzymes and AAL 2002/3 (n=37)

  19. Variation of DP enzymes and AAL 2002/3 (n=37) Correlation (r) between AAL and DP enzymes 2002/3

  20. Variation of DP enzymes and AAL 2005: Maltster: Gairdner

  21. Variation in a Maltster’s production

  22. Variation in a Maltster’s production

  23. Application of DP enzyme testing: Brewing Case Studies

  24. Variation in a brewers malt supply i

  25. Variation in a brewers malt supply ii

  26. Commercial brewery fermentability variability explained by DP enzyme levels i

  27. Commercial brewery fermentability variability explained by DP enzyme levels ii

  28. Commercial brewery fermentability variability explained by DP enzyme levels iii

  29. An Improved malt description?

  30. The effect of malt blending on fermentability

  31. The influence of blending on fermentability Clipper and Flagship DP enzyme quality

  32. Practical implications for delivering malt that satisfies brewers

  33. Considerations • If so, what are the implications in the quality lab? • Discontinue DP evaluation? • Analyses to be done: • -amylase thermostability specific to variety. • KI already routinely measured. • New lab tests to be implemented: • -Amylase activity - Betamyl®. • a-Amylase activity - Ceralpha®. • Limit dextrinase - Limit DextriZyme®.

  34. Maltster & brewer advantages? • More accurate description of malt quality. • Malt blending to balance DP enzyme levels. • Greater malt consistency and predictability. • Reduced surprises in brew house. • Warn brewers if malt not in spec • Better targeted selection by barley breeders.

  35. Co-ordination of Malt Supply Chain • Maltster • monitoring • logistics • steeping • germination • blending • Breeder • genes • Grain handler • - marketer • prediction • logistics • segregation • Grower • region • agronomy • rainfall? • Brewer • informed • blending • mashing

  36. Conclusions • Improved prediction of malt fermentability based on: • -amylase thermostability and activity. • Level of a-amylase activity. • Limit dextrinase level. • Modification / KI. • No one DP enzyme more important the others • Is the malt DP specification redundant? • Understanding has the potential for growers, breeders and maltsters to provide brewers with more consistent and predictable malt.

  37. Acknowledgments Assistance: Australian Malting and Brewing Industry, particularly Cascade Brewery Company Funding: Grains Research and Development Corporation, Grant: UT 00012, ABB Grain, J Boag & Son, Barrett Burston Maltings, Coopers Brewery, Fosters Group, International Malting Company, Joe White Maltings, Kirin Australia, Lion Nathan, University of Tasmania.

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