alpha-Casein improves the gel properties of dried egg white.
The effects of addition of alpha-casein (alpha-CN) to dried egg white (DEW) were investigated by measuring transparency, hardness, and water-holding capacity (WHC) of the heat-induced gels. A DEW concentration of 8% (w/w) was required for formation of a self-supporting gel following heating at 80 degrees C for 20 min at pH 7. Solutions of alpha-CN, even up to a protein concentration of 12% (w/w), did not gel under the same conditions. The addition of alpha-CN (0.5-4%) to 8% DEW caused the increase in gel hardness gels, as compared with DEW gels alone at a total amount of protein concentrations, and the mixed gels became transparent with the increase of added alpha-CN concentrations. The 10% mixed protein solutions of alpha-CN (3-6%) and DEW (4-7%) formed transparent gels, although each protein did not gel individually at their protein concentrations. Mixture with 2:8 mixing ratio of alpha-CN to DEW at a total protein concentration of 10% showed synergistic effects in improving DEW gel properties above pH 7 and below 25 mM NaCl. The improvements (hardness, transparency, and WHC) of DEW gel by alpha-CN seem to be caused mainly by the inhibition of alpha-CN against heat coagulation of DEW protein.
Matsudomi
Naotoshi
N
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan. naotoshi@yamaguchi-u.ac.jp
Kanda
Yuka
Y
Moriwaki
Hiromi
H
D002364:Caseins; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004529:Egg White; D005503:Food Additives; D005519:Food Preservation; D005782:Gels; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration
D002364:Caseins; D005503:Food Additives; D005782:Gels