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United States Department of Agriculture

Agricultural Research Service


item Henson, Cynthia
item Karpelenia, Charles

Submitted to: Journal of American Society of Brewing Chemists
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A malt's ability to convert starch to fermentable sugars is typically assessed by measuring alpha-amylase activity and diastatic power (DP). Although we know four enzymes probably contribute to starch conversion, alpha-amylase is the only individual enzyme activity routinely measured. The other three enzyme activities are not specifically accounted for in the DP measurement. We do not know if specific measurements of beta- amylase, alpha-glucosidase and limit dextrinase activities would better predict malt quality than alpha-amylase and DP measurements, nor do we know the contributions of the individual enzyme activities to DP. This study was to first determine the relationships between the individual enzymes activities and DP. Malts from two of the three locations in the Western Regional Uniform nurseries and from two of the four locations in the Mississippi Valley Uniform nurseries were selected to study based on their alpha-amylase and DP values determine using ASBC methods. Malts from one location in each uniform nursery had no significant correlation between alpha-amylase and DP (population 1) and malts from the other location in each nursery had a strong correlation (population 2). None of the four enzyme activities significantly correlated with DP when population 1 malts were analyzed with enzyme specific assays. Analysis of population 2 malts with enzyme specific assays showed alpha-amylase and beta-amylase from both locations were correlated with DP. Alpha- glucosidase from one location was positively and significantly correlated. Limit dextrinase was not correlated with DP from either location. We will next determine relationships between the four enzyme activities in the malts with production of fermentable sugars during mashing.

Last Modified: 08/20/2017
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