Protein experiment

About (not) consuming fresh raw fish and fresh raw egg yolks
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homeslice
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Protein experiment

Post by homeslice »

hi i am taking a bio class and i have chosen to do an expirment testing protein quality before and after it is cooked. i will either use egg or fish. can any please tell me how i can do this, what materials ect... any help is greatly appreciated thanks!
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Oscar
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Post by Oscar »

Sounds interesting :)
RRM might have some ideas, but he only reads the forum on tuesday/wednesday.
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RRM
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Post by RRM »

I think its most easy to use egg, as there is no debate about which part of it to compare (other than egg yolk or egg white).
I dont know what materials you need to use, but im sure you can find that information in studies in which they did examine the presence of amino acids in foods. I will look them up for you.

To test protein quality, you will be required to measure total protein (through nitrogen) and how much of a certain amino acid is present in a given sample of food.
In fact, you would only need to measure protein, methionine and cysteine, but if you want to perform the test extensively, you could also measure the presence of ALL amino acids (which is about 9 times more work).

After having measured the presence of amino acids, you may compare their absolute presence (per food quantity) and their ratio to total protein (before and after cooking, of course)
As the combination of methionine and cystein is overall by far the most scarsely available in food on average, and there are 18 amino acids in total (regarding amino acid requirements) protein quality is measured by:
(methionine + cysteine) x 9 / total protein.
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Mr. PC
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Post by Mr. PC »

Hmm, I never noticed RRM's posting pattern. Why Tuesday and Wednesday?

Wouldn't it also be (possibly more) important to measure the creation of HCA etc. in cooked proteins?
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RRM
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Post by RRM »

Mr. PC wrote:Hmm, I never noticed RRM's posting pattern. Why Tuesday and Wednesday?
Thats my weekend!
= much more time to post.
(but i also post on other days)
Wouldn't it also be (possibly more) important to measure the creation of HCA etc. in cooked proteins?
Yes!
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