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Chemical Modification of Egg White with 3, 3‐Dimethylglutaric Anhydride
Author(s) -
GANDHI S. KRISHNA,
SCHULTZ JAMES R.,
BOUGHEY FRED W.,
FORSYTHE RICHARD H.
Publication year - 1968
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1968.tb01343.x
Subject(s) - egg white , lysozyme , chemistry , hydrolysis , lysine , mole , analytical ultracentrifugation , new zealand white rabbit , ultracentrifuge , chromatography , biochemistry , amino acid , biology , paleontology
SUMMARY— Egg white, near its normal concentration, was reacted at 25°C, pH 9.0, with levels of 3,3‐dimethylglutaric anhydride (DMGA) from 0 to 60 mol/mol egg white protein (EWP) (assuming egg white to have an average mol wt of 50,000). Analysis for amino acids and functional groups showed about 26% of the lysine residues reacted at 15 mol DMGA/mol EWP. Sulfhydryls are more resistant to reaction with 60% unreacted at 150 mol DMGA/mol EWP. Electrophoresis indicates significant changes in net charges on the protein, particularly on lysozyme which migrates anodically in six separate bands at higher DMGA levels. Ultracentrifugation sedimentation data suggest no hydrolysis or aggregation changes. Foam formation is not seriously altered, but the heat coagulation properties, as evidenced by angel cake failures, are changed. As measured by viscosity, light transmission and aerating ability, DMGA exerts a protective action against the effect of heat on these properties.