Changes in Composition of Crude Egg Protein Preparations when Kept Under Refrigeration for Several Years

Abstract

As part of an experiment to study the effect of a methionine and lysine deficient diet on the amino acid composition of eggs, crude white and yolk proteins were separated from the eggs (Evans, Davidson and Butts, 1950). The white protein was nothing more than the dried egg whites and contained an average of 80.0 percent crude protein (N×6.25). Yolk protein preparations were made by separating the yolk of the hard boiled egg from the white and extracting the broken up yolk first with cold ethanol in a beaker with decantation and then in the Goldfisch extractor first with ethanol and then with diethyl ether. The ether was removed by heating the material in a beaker on the steam bath. The yolk protein preparations contained on the average 85.5 percent crude protein (N×6.25). Nitrogen was determined by the Kjeldahl-Wilforth-Gunning method (A.O.A.C., 1950).One-gram samples of protein preparation were hydrolyzed by …