Phase separation in ternary composite cold-set gel of egg yolk/κ-carrageenan/xanthan: Study on rheological and proton mobility properties

Abstract

The effects of sodium tripolyphosphate and sugar on cold-set gel properties of egg yolk/κ-carrageenan/xanthan gum mixed dispersions were investigated by zeta potential, rheological measurements, gel textural analysis and low-field nuclear magnetic resonance (LF-NMR). As the yolk content increased to the 5 g/100 mL in aqueous systems, phase separation of mixed gel could be observed, due to the relatively rough gel appearance. Furthermore, the addition of phosphate could significantly improve the phase separation of mixed gels by elevating the pH and reducing zeta potential. The increase in the content of yolk and sugar brought an enhancement in gel storage modulus, while the addition of phosphate induced a dramatic decrease in the gelation rate of mixed gels. Textural analysis confirmed that hydrogen bonding interaction was the important force, which determined gel strength of the ternary composite cold-set gelation system. The result of LF-NMR revealed that there was a negative correlation between the decrease of proton mobility of immobilization water and the increase of gel strength in different sample series.