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Assessing the Impact of the Level of Diastatic Power Enzymes and Their Thermostability on the Hydrolysis of Starch During Wort Production to Predict Malt Fermentability

Citation

Evans, DE and Collins, H and Eglinton, J and Wilhelmson, A, Assessing the Impact of the Level of Diastatic Power Enzymes and Their Thermostability on the Hydrolysis of Starch During Wort Production to Predict Malt Fermentability, Journal American Society of Brewing Chemists , 63, (4) pp. 185-198. ISSN 0361-0470 (2005) [Refereed Article]

DOI: doi:10.1094/ASBCJ-63-0185

Abstract

In this study, commercially produced malts were used for small-scale simulated mashing trials to investigate the impact of differences in the level and thermostability of malt diastatic power (DP) enzymes on the resultant wort fermentability. A modified European Brewery Convention/American Society Brewing Chemists mashing protocol was used with mash-in temperatures ranging between 45 and 76C for full-malt and 30% rice adjunct mashes. Malt extract yield varied little with mashing temperature for most varieties in this temperature range. However, the fermentability, maltose content, and free amino nitrogen of that extract was considerably affected by mashing temperature with 65C achieving the highest fermentability for all malt varieties. Multilinear regression analysis of full-malt and rice adjunct mashing trials at 65C using 43 commercial malts showed that the level of α-amylase and total limit dextrinase activity, Kolbach Index, and the total β-amylase activity level and thermostability were the most important malt quality predictors of wort fermentability. These conclusions suggest that the conventional DP assessment could be replaced with the measurement of its component enzymes outlined above so that maltsters could better satisfy brewers malt quality expectations by blending and defining their malt quality in terms of these fermentability predicting factors. This information would be particularly useful to brewers who brew with multiple varieties and blends from different suppliers. The focus on individual enzyme characteristics by barley breeders is likely to provide selection targets that are more accurate and achievable.

Item Details

Item Type:Refereed Article
Keywords:alpha-amylase, beta-amylase, limit dextrinase
Research Division:Agricultural and Veterinary Sciences
Research Group:Crop and Pasture Production
Research Field:Crop and Pasture Biochemistry and Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Winter Grains and Oilseeds
Objective Field:Barley
Author:Evans, DE (Dr David Evans)
ID Code:30745
Year Published:2005
Web of Science® Times Cited:56
Deposited By:Agricultural Science
Deposited On:2005-08-01
Last Modified:2013-01-31
Downloads:0

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