Studies on the Characterization of Ovomucin and Chalaza of the Hen's Egg

Abstract

A study was made on the electrophoretic analysis, fractionation and characterization of chalaza, and ovomucin from thick and thin albumen of the hen's egg. The chalaza and ovomucins were confirmed to be composed of three components which the molecular weights were estimated to be 150,000, 220,000 and 400,000 daltons, and named (~1, (~2 and p, respectively. They were fractionated into carbohydrate poor (al and a2 mixture) and rich (p) components by gel filtration in the presence of SDS and 2-mercaptoethanol. In the amino acid and carbohydrate compositions, differences were observed only in the carbohydrate compositions of P-components. Sonication facilitated solubilization of the ovomucin, but some signs of degradation of subunit components were observed.

Ovomucin content and composition in chicken eggs with different interior quality

“…Amino acid proportions were in the same range as those reported by Itoh and coworkers 9 and by Awade  and coworkers. 23 It appears that differences observed in ovomucin amount or subunit proportions were not due to signi®cant changes in the amino acid make up of ovomucin.…”

“…Each albumen fraction was mixed with 10 volumes of water, stirred with a magnetic stirrer, centrifuged, and the precipitate lyophilised to give the crude water-insoluble ovomucin preparation. 9 Further puri®cation of thick albumen ovomucin involved washing the water-insoluble ovomucin with approximately 15 volumes of a 2% potassium chloride solution and centrifuging. The washed, insoluble material was lyophilised and stored at À70°C.…”

“…Ovomucin subunits were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), 9 with a discontinuous gel buffer system.…”

“…3±7 Ovomucin is generally accepted as a key component in maintaining the viscous nature, 8 and consequently the HU score and height of the egg's thick albumen. 9,10 During storage of shell eggs, thinning of egg albumen takes place. This thinning is associated with disaggregation of ovomucin's a and b-subunits.…”

The allergenicity of ovomucoid and the effect of its elimination from hen's egg white

“…Ovomucin was prepared as described by Itoh et al 20 Commercially spray-dried egg white powder was kindly provided by Inovatech (Vancouver, BC, Canada). The ovalbumin, ovomucoid, ovotransferrin and lysozyme were further puri®ed using HPLC ion exchange chromatography.…”