Turbidity of egg albumin and egg white heated at various pH values and
NaCl concentrations were measured using a microplate system. Small sa
mples could be treated in a short time. The effects of pH and NaCl con
centration on the turbidity of the samples after heating were clearly
shown by this method and quantitatively by the contour graph. Turbid s
amples were formed by heating at pH values around pI values of constit
uent proteins and at high NaCl concentration. On the other hand, trans
parent gels and sols were formed on heating at pH values distant from
pI values and at low NaCl concentration.