User:Nadiezda Fernandez-Oropeza/Notebook/Notebook/2010/10/19

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Whole Casein Solution

  • This entry describes the preparation process of the Whole Casein (W-Casein) solution.

Prepare a 20 ml PEM solution in an Erlenmeyer flask. This can be done just by diluting the 10xPEM solution stored in aliquots, with a ration 2:18.

  • Andy Maloney 14:19, 26 October 2010 (EDT): This is important as not all Erlenmeyer flasks will work with this setup. The flask has to have a ground glass neck with this odd numbering system ($19/22) on it. This is a sizing description and is some standard in the chemistry world. Only $19/22 flasks will fit 19/22 condensers. It's important we don't loose this thing as it is the only one we have.

The concentration of the whole Casein solution is 1 mg/ml. Therefore, we need to add 20 mg of Casein to the PEM solution.

Once ready, put a stirring bar into the Erlenmeyer flask. Then, place the flask over a heating-stirring unit. From the top, connect it to a Liebig condenser. Let the solution be heated, stirred and condensed for 15 minutes.

    • NOTE: The condenser forms a closed loop as one of its hoses connects to a bucket of iced water and a fish tank pump and the other hose is connected to the same bucket but with a different tube. One of the ends is attached to the Erlenmeyer flask and the upper end is left open to the atmosphere.

During those 15 minutes, we can observe how the particles of casein seem to get bigger as they go into solution. Moreover, we will observe the formation of foam, which is a good indicator of the presence of proteins.

After the 15 minutes let the system to cool down and put the solution on the freezer overnight.