Spectrophotometric Determination of Protein and Fat in Milk Simultaneously

Abstract

A completely clear solution was obtained by adding 5 ml of 97% acetic acid to 0.05 ml of whole milk. The protein was calculated from the absorbance at 280 mμ. Turbidity depending on fat content was developed thereafter by adding 2.5 ml of a solution containing 20% urea and 0.2% imidazole. The fat was determined from absorbance at 400 mμ with a round cuvette. This method does not require prehomogenization of milk for turbidity measurement, because of a dispersing effect by the combination of reagents. Application of this method to other food products is suggested. © 1970, American Dairy Science Association. All rights reserved.