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Thread: Proteinase A

  1. #1
    Join Date
    Jun 2010
    Location
    Edinburgh, Scotland
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    69

    Proteinase A

    Odd question, I searched the internet for an answer but couldn't find it. Does anyone know the inactivation temperature for Proteinase A?
    Roger Greene

  2. #2
    Join Date
    Oct 2005
    Location
    Salt Lake City, UT
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    474

    here you go

    According to Springer's it's 95 deg, with maximum activity between 50 and 60. Acid denature occurs at ph 6.0 and is irreversable.

    Hope that helps.

  3. #3
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    Jun 2010
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    Edinburgh, Scotland
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    that's celsius right?
    Roger Greene

  4. #4
    Join Date
    Oct 2005
    Location
    Salt Lake City, UT
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    474

    whoops...

    Yup...deg C. Sorry...I assume everyone uses C, and that often gets me into trouble.

    Just curious as to why you want to know? It took me a few minutes to find it...

  5. #5
    Join Date
    Jun 2010
    Location
    Edinburgh, Scotland
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    juist something interesting

    Well I was just curious if pasteurization (flash or tunnel) would have any effect on the activity of Proteinase A in the packaged beer.
    Roger Greene

  6. #6
    Join Date
    May 2009
    Location
    Oregon
    Posts
    31

    Pasteurization and Proteinase A Deactivation

    From 2010 edition of Kunze, Technology Brewing & Malting:

    p. 515, "To achieve microbiological safety, recovered yeast has to be flash pasteurized with 40 to 100 PU, which also stops the proteinase A activity."

    p. 507 "...the yeast excretes a proteinase A, which leads to a considerable deterioration of the foam due to the breakdown of foam positive substances in the beer. This is of particular importance for beers where no heat treatment occurs before filling and where proteinase A passes into the finished beer.'

    Hope this helps.
    Mark
    http://www.hiddenwellbrewery.com

  7. #7
    Join Date
    Oct 2002
    Location
    Tadcaster, Yorkshire, UK
    Posts
    1,070
    That was a timely extract from Kunze.

    I have been looking at a recovered beer pasteuriser for different reasons, and now I know we have another reason for not dropping too low - not that I would have expected to get down to normal sales beer PUs without micro issues anyway due to the loading pre-pasteuriser.

    Thanks
    dick

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