Yes, it is possible. You may need to dry the sample for fat determination but you don't need to dry the sample for protein estimation.

Liquid sample could be used for Crude protein determination. Generally 2g of wet sample were taken for the protein estimation in kjeldahl method. It can be later converted in to dry weight basis by estimating the moisture content of sample. For Fat estimation, I dont have idea

Yes, both of them (Gerber method for fat and kjeldahl for protein) are possible for milk and milk is a liquid.

yes it is possible

Gerber method for fat content and Kjeldahi for crude protein are applicable for milk samples - for protocols, follow the ISO standards

Sarafa Adeyemi Akeem Thank you.

I want to do it without drying.

Vignaesh Dhanabalan Thank you. Could you please provide me the detailed procedure for CP estimation?

Thank You Hamed Hassanzadeh

Thank you Kasturi Chattopadhyay

Sami GHNIMI Thank you.

Determination of crude protein (AOAC 2005)

Crude protein was measured according to the method of AOAC, 2005. 2 g of the wet sample was weighed into the digestion flask, 4-5 g of digestion mixture (CuSO₄ and K2SO₄ in 1:5 by weight), and add 10 ml of concentrated H2SO4were added to the digestion flask. Digestion of the sample was carried out

Distillation unit

The distillation process was started by adding 10 ml of boric acid solution(2%) and 4 ml of NaOH(40%) and 2 ml of the made up solution was transferred along with 4 ml NaOH to the digestion tube and placed it in the distilling unit. Then the receiver flask was placed on the platform of the distilling unit with 10 ml of boric acid containing one or two drops Tashiro’s indicator. The contents were titrated with 0.1N H2SO4 until the change in appearanceof pink color from green color. Crude protein is determined by multiplying 6.25 with the percentage nitrogen.

Total nitrogen (%, wet weight) = (14×N×X×100) / (1000×V×W) ×100

Hence, % Protein = % Total nitrogen 6.25 (conversion factor)

Where,

N = normality of H2SO4

X = ml of standard H2SO4 required for titration of samples

V = aliquot (ml) of digested extract taken for distillation

W =weight (g) of sample

Conversion of Protein from wet weight basis to dry weight basis

= 100*Total Protein / (100-Moisture Content)

Vignaesh Dhanabalan Thank you Dr. Dhanabalan.

Yes it is possible. See AOAC procedure for crude protein and fat determination for liquid like milk

Thank you Dr. Gowe