Amino Acid Analysis of Shell Membranes of Eggs From Young and Old Hens Varying in Shell Quality

The amino acid composition of egg shell membranes was determined on membranes from eggs from young (28 weeks) and old (72 weeks) hens having low, medium or high shell deformation. The amino acid composition of the shell membranes of the various treatment groups showed relatively small differences due to treatment. The shell membranes contained relatively large amounts of the sulfur containing amino acids, cystine (9–10%) and methionine (3–4%), suggesting that the protein is a keratin since no hydroxyproline was found. The use of stepwise discriminant analysis of the amino acid data enabled correct classification of the shell membranes by treatment groups and indicated the amino acids of greatest importance in the classification of the shell membranes.