Compositional analysis and structural elucidation of glycosaminoglycans in chicken eggs

Abstract

Glycosaminoglycans (GAGs) have numerous applications in the fields of pharmaceuticals, cosmetics, nutraceuticals, and foods. GAGs are also critically important in the developmental biology of all multicellular animals. GAGs were isolated from chicken egg components including yolk, thick egg white, thin egg white, membrane, calcified shell matrix supernatant, and shell matrix deposit. Disaccharide compositional analysis was performed using ultra high-performance liquid chromatography-mass spectrometry. The results of these analyses showed that all four families of GAGs were detected in all egg components. Keratan sulfate was found in egg whites (thick and thin) and shell matrix (calcified shell matrix supernatant and deposit) with high level. Chondroitin sulfates were much more plentiful in both shell matrix components and membrane. Hyaluronan was plentiful in both shell matrix components and membrane, but was only present in a trace of quantities in the yolk. Heparan sulfate was plentiful in the shell matrix deposit but was present in a trace of quantities in the egg content components (yolk, thick and thin egg whites). Most of the chondroitin and heparan sulfate disaccharides were present in the GAGs found in chicken eggs with the exception of chondroitin and heparan sulfate 2,6-disulfated disaccharides. Both CS and HS in the shell matrix deposit contained the most diverse chondroitin and heparan sulfate disaccharide compositions. Eggs might provide a potential new source of GAGs.

Fig. 1

Schematic figure of a chicken egg and a flow chart of sample processing.

Fig. 2

Extracted ion chromatographs (EICs) of AMAC-labeled KS and its disaccharides in various egg components analyzed by LC-MS. A. KS disaccharide standards; B. yolk; C. thick egg white; D. thin egg white; E. membrane; F. shell matrix supernatant; G. shell matrix deposit.

Fig. 3

EICs of AMAC-labeled CS and HA and its disaccharides in various egg components analyzed by LC-MS. A. CS and HA disaccharide standards; B. yolk; C. thick egg white; D. thin egg white; E. membrane; F. shell matrix supernatant; G. shell matrix deposit.

Fig. 4

EICs of AMAC-labeled HS and its disaccharides in various egg components analyzed by LC-MS. A. HS disaccharide standards; B. yolk; C. thick egg white; D. thin egg white; E. membrane; F. shell matrix supernatant; G. shell matrix deposit. No. 1 peaks in Fig. 3A, 3B, 3C represented 0S disaccharides.