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Improvement of Functional Properties of Ovotransferrin by Phosphorylation through Dry-heating in the Presence of Pyrophosphate |
Yoko Hayashi, Can-Peng Li, Hirofumi Enomoto, Hisham R. Ibrahim, Yasushi Sugimoto, Takayoshi Aoki* |
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Correspondence:
Takayoshi Aoki, |
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Abstract |
Ovotransferrin (OTf) was phosphorylated by dry-heating in the presence of pyrophosphate at pH 4.0 and 85??C for 1 and 5 d, and the functional properties of phosphorylated OTf (PP-OTf) were investigated. The phosphorus content of OTf increased to 0.91% as a result of phosphorylation and the electrophoretic mobility of PP-OTf also increased. Although the solubility of dry-heated OTf slightly decreased, the decrease was reduced by phosphorylation. The stability against heat-induced insolubilization of OTf was somewhat improved by phosphorylation, but more than 70% of PP-OTf was insolubilized when it was heated at 70??C for 10 min at pH 7.0. However, heat-induced insolubilization of PP-OTf was reduced when it was heated in the presence of phosphorylated ovalbumin. This may explain the excellent stability of phosphorylated egg white protein against heat-induced insolubilization which was reported previously. The emulsifying property of OTf was also somewhat improved by phosphorylation. The calcium phosphate-solubilizing ability of PP-OTf was enhanced. Although the degree of phosphorylation of OTf by dry-heating in the presence of pyrophosphate was similar to that of ovalbumin, the improvement of properties of PP-OTf was considerably different from those of phosphorylated ovalbumin. |
Keywords:
Ovotransferrin; Phosphorylation; Dry-heating; Functional Property |
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