Abstract: In the processing of preserved eggs (pidan), OH in alkaline solution osmose into eggs mainly in the first week. In this period, the pH of albumen reach the highest point. Then the pH of albumen decrease when OH- osmose into yolk from albumen, later the pH increase again. And major effect of metal ions (Pb2+、Zn2+、Cub2+ )is to reduce the speed of OH- osmosing into eggs, the results which metal ions hinder OH- osmosing is different as the different physical and chemical character of ions.

Key words: Pidan ions osmosing OH~-