Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Yogurt production

  1. Mar 17, 2005 #1
    What enzymes are involved in the production of yogurt (the fermentation of milk in particular), and what do these enzymes do?
  2. jcsd
  3. Mar 17, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It is not an enzyme that is responsible for te production of yogurt. It is a group of bacteria called the lactic acid bacteria which include the lactococcus and lactobacillus genus.

    Basicly, the lactobacillus will start the yogurt fermentation by converting the lactose (sugar) to lactic acid. the acid produce will drop the pH of the milk therefore changing the chemistry. Due to the pH drop, the protein coagulates and forms what we known as yogurt.
  4. Mar 17, 2005 #3
    Yes, but are any enzymes involved at all? Or for that matter, are any enzymes produced or present in yogurt before and/or after production?
  5. Mar 17, 2005 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The bacteria due produce enzymes that are responsible for transforming lactose to lactic acid and if you did an analysis for the enzymes would might see different enzyme at different time point.

    However there is not enzyme present in the milk that would cause the fermentation of yogurt.
  6. Mar 17, 2005 #5
    Is that enzyme that the bacteria produce called "lactase"? If so, are there any other enzymes that are produced by the bacteria?
  7. Mar 17, 2005 #6


    User Avatar
    Science Advisor
    Homework Helper

    There is only one enzyme that I am aware of, necessary for yogurt culture and that is β-galactosidase.

    Some commonly used bacteria to make yogurt, are: Lactobacillus bulgaricus, Lactobacillus acidophilus & Streptococcus salivarius.

    They absorb the lactose across their membrane and catabolize the lactose into two smaller sugars galactose and glucose by producing the enzyme β-galactosidase (synonym for lactase). Their byproduct is lactic acid which passes out of the bacteria, lowers the pH of the medium, which as iansmith also mentioned, coagulates the milk protein into a curd just like cheese and tofu. :smile:

    So there are no additional enzymes found in the milk or yogurt. All the biochemistry is internal to the bacteria. The bacteria will catabolize the galactose and glucose using enzymes. But you can find out what those are in the library, in any introductory biochemistry book. :rolleyes:
  8. Mar 18, 2005 #7
    These other enzymes...is there anywhere on the net where I can further research them? (I'm kinda tight on time and space, so going to a library/textbook isn't really an option right now)
  9. Mar 18, 2005 #8
    What books ? what titles are they ?
  10. Mar 18, 2005 #9
    Well , I want to make yogurt to eat only
    after reading your scientific posts
  11. Mar 21, 2005 #10


    User Avatar
    Science Advisor
    Homework Helper

    A couple that come to mind are:

    Lehninger Principles of Biochemistry
    by Albert L. Lehninger, David L. Nelson, Michael M. Cox
    ISBN: 0716743396


    by Lubert Stryer, John L. Tymoczko, Jeremy Mark Berg

    makes for some great late night reading :biggrin:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Yogurt production
  1. RT-pPCR products? (Replies: 1)

  2. Tm of a PCR product? (Replies: 4)