Detecting the presence of proteins???

A.J.B.B

Hi guys,

I have a pretty random question that I'm hoping one of you may be able to answer (since I know absolutely zero about chemistry). I'm curious to find out what methods there are for detecting the presence of proteins. For instance, in analysing a given food item, how is it possible to deduce that X% of the item is protein?

A random and possibly stupid question, but thanks in advance!

Reply 1

Kallisto

Entertainment Forum Helper

22

To be honest I don't know a single method to determine the presence of proteins and the quantity of them in food. But there is a Wikipedia-link which show you up many methods to detect the proteins:

http://en.wikipedia.org/wiki/Protein_methods

Perhaps one of these methods can be used by food items?

EDIT

After some researches, I have found out, that the biuret test can be used for detecting proteins in food items indeed. I was not sure, whether it is possible for any food items or not. Milk for instance is suited for this test. By this test milk and sodium hydroxide solution are added in a test tube in equal shares (the same quantity). After shaking the test tube, copper sulfat is added to the test tube. After that the solution gets a purple colour what detects the proteins in the milk. This colour is causing by the copper ions in the solution which enable a bond of the peptides to a protein molecule. However this biuret test doesn't work when the food item has a higher protein concentration...

(edited 9 years ago)

Reply 2

A.J.B.B

OP

1

Original post by Kallisto

To be honest I don't know a single method to determine the presence of proteins and the quantity of them in food. But there is a Wikipedia-link which show you up many methods to detect the proteins:

http://en.wikipedia.org/wiki/Protein_methods

Perhaps one of these methods can be used by food items?

EDIT

After some researches, I have found out, that the biuret test can be used for detecting proteins in food items indeed. I was not sure, whether it is possible for any food items or not. Milk for instance is suited for this test. By this test milk and sodium hydroxide solution are added in a test tube in equal shares (the same quantity). After shaking the test tube, copper sulfat is added to the test tube. After that the solution gets a purple colour what detects the proteins in the milk. This colour is causing by the copper ions in the solution which enable a bond of the peptides to a protein molecule. However this biuret test doesn't work when the food item has a higher protein concentration...