Colorimetric Method for Estimation of Proteose-Peptone in Milk

Abstract
The milk serum obtained after the removal of casein and whey proteins by adjusting the pH of heated milk to 4.5, was used for estimating proteose-peptone. Color was developed with such serum before and after treatment with trichloroacetic-acid with Folin''s phenol reagent and read at 750 m[mu]. Absorption maximum, color-concentration proportionality, added recovery and comparison of N value with colorimetric value for proteose-peptone satisfied the requirements for colorimetric determination. Advantages offered by the method are simplicity and sensitivity of the reaction. Using this method, average values of 220.9 [plus or minus] 9.9 mg and 172.1 [plus or minus] 7.6 mg of proteose-peptone/100 ml of cow and buffalo milk were obtained, respectively.