title: Improvement of functional properties of egg white protein through phosphorylation by dry-heating in the presence of pyrophosphate.
abstract: Egg white protein (EWP) was phosphorylated by dry-heating in the presence of pyrophosphate at pH 3.0-7.0 and 85 degrees C for 1 and 5 days, and the functional properties of the phosphorylated EWP (PP-EWP) were investigated. The phosphorylation was accelerated with a decrease of pH from 7.0 to 3.0 and for heating times from 1 to 5 days. The phosphorus content of EWP increased approximately 1.05% by dry-heating at pH 4.0 and 85 degrees C for 5 days in the presence of pyrophosphate, which was higher than that of casein. The electrophoretic mobility of EWP increased with an increase in the phosphorylation level. The surface hydrophobicity of EWP increased by phosphorylation. The heat stability, emulsifying properties, and digestibility of EWP were improved by phosphorylation. The calcium phosphate-solubilizing ability of EWP was enhanced by phosphorylation. A firmer and transparent heat-induced gel of PP-EWP was obtained, and the water-holding capacity of heat-induced PP-EWP gel was higher that that of the control. These results suggest that phosphorylation by dry-heating in the presence of pyrophosphate is a useful method for improving the functional properties of EWP.
authors.affiliation: United Chair of Applied Resource Chemistry, Course of Bioresource Science for Processing, United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan.
authors.forename: Can-Peng
authors.initials: CP
authors.lastname: Li
authors.forename: Hisham R
authors.initials: HR
authors.lastname: Ibrahim
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sugimoto
authors.forename: Hajime
authors.initials: H
authors.lastname: Hatta
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Aoki
mesh_terms: D011756:Diphosphates / Q000737:chemistry*; D004527:Egg Proteins / Q000737:chemistry*; D015387:Egg Proteins, Dietary; D005782:Gels / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D010758:Phosphorus / Q000032:analysis; D010766:Phosphorylation; D012995:Solubility
chemical_list: D011756:Diphosphates; D004527:Egg Proteins; D015387:Egg Proteins, Dietary; D005782:Gels; D010758:Phosphorus