Question

What are the names of the two chemical procedures used to analyze crude protein in animal feed

Answer 1

ANS:- crude protein is the total protein. it depends on the nitrogen content of the food proteins.

A) DUMAS METHOD B) LOWRY METHOD

A) DUMAS METHOD :- This method determines the combusting a sample in a high temperature of 800-900°C in the presence of O2. This is release of Co2 , water and nitrogen. The gases are passed over columns(like potassium hydroxide aqueous solution) that absorb the Co2 and water. A column containing a thermal conductivity detector at the end is then used to separate the nitrogen from any residual carbon dioxide and water and the remaining nitrogen content is measured. The instrument is calibrated by determining a material that is pure and nitrogen concentration. The measured signal from the thermal conductivity detector for the unknown sample can be converted into a nitrogen content. As with the Kjeldahl method, the concentration of nitrogen in a sample to the crude protein content is performed using conversion factors which depend on the particular amino acid sequence of the measured protein.

B) LOWRY METHOD :- this method is treated with reagent that is Folin-Cioclateu reagent. in this copper ions with peptide bonds under alkaline conditions . Folin- Cioclateu reagent is a mixture of phosphotungstic and phosphomolybdic acid.