Paper on Limit Dextrinase

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Bryan R
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Paper on Limit Dextrinase

Postby Bryan R » Thu Oct 15, 2015 9:33 am

"Limit dextrinase (EC is debranching enzyme catalyzing the hydrolysis of a-1,6-
glucosidic linkages in starch. The role of this debranching enzyme in beer brewing has been
questioned due to its assumed heat lability. In the present work the effectiveness of limit
dextrinase was studied under conditions mimicking brewery practice rather than in buffer
solution. It was demonstrated that typical conversion temperatures of 63-65 °C and mash pH
of 5.4-5.5 favour the action of malt limit dextrinase. The temperature optimum for the limit
dextrinase of malt extract was 60-62.5° C, as opposed to 50°C for purified limit dextrinase.
Lowering the mash pH from 5.8 to 5.4 increased wort fermentability due to increased limit
dextrinase activity. Wort fermentability was more strongly correlated to the free limit
dextrinase activity of malt than to the a- and fi-amylase activities."
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Ancient Abbey
German Brewing
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Re: Paper on Limit Dextrinase

Postby Ancient Abbey » Fri Jan 22, 2016 9:39 am

I knew there had to be more to limit dextrinase. I never could understand how the enzyme that was responsible for breaking up amylopectin (80% of the total starch in barley!) branches hit its optimum so far below gelatinization and saccharification temps. Yet another reason to hochurz mash ;-)
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Re: Paper on Limit Dextrinase

Postby lhommedieu » Sat Feb 13, 2016 10:53 am

The CW has been that the actions of limit dextrinase takes place at lower temperatures, as stated above; if it survives the higher temperatures that occur during the first rest (and within a specific band of pH), does this mean that its actions on limit dextrins left over from alpha and beta will result in a higher fermentability?

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