Combined effects of NaOH, NaCl, and heat on the gel characteristics of duck egg white

Abstract

In this paper, the effects of NaOH, NaCl, and heat on the appearance, physical characteristics, and gel structure of duck egg white (EW) jointly induced by NaOH, NaCl, and heat were investigated. Results showed that the absolute value of zeta potential (TAV-ZP) of gel samples increased, hunter whiteness decreased, gel opacity decreased, and the microstructure of gel appeared as a loose network structure with increased NaOH addition. With the increase of NaCl addition, TAV-ZP of gel samples decreased, hunter whiteness increased, gel opacity increased, the microstructure of gel became dense. With the increase of heating temperature, TAV-ZP of gel samples decreased, hunter whiteness decreased, gel opacity increased, the microstructure of gel became dense first and then loosened. The results of SDS-PAGE, surface hydrophobicity, T2, hardness, cohesiveness indicated that protein molecules underwent cross-linking, aggregation, and unfolding during duck EW gelation jointly induced by NaOH, NaCl, and heat. The results of strain-stress curve showed that all gel samples had a good anti-compressed ability. The results of central composite design showed that the best treatment of gel was heating temperature 91 °C, NaOH 0.48%, and NaCl 0.3%.