Influence of flaxseed gum and NaCl concentrations on the stability of oil-in-water emulsions

Abstract

In this work, we investigated the influence of the addition of flaxseed gum (FG) (0.1–0.5%, w/w) and NaCl (0–0.6 M) on the stability of 10% (w/w) melted lard emulsions. The particle size, ζ-potential, rheological properties, creaming stability, microstructure, and nuclear magnetic resonance spectra of the emulsions were analyzed. The results showed the particle size in emulsions significantly decreased with increasing FG concentrations and the smallest droplets in emulsions with 0.5% (w/w) FG were obtained. The rheological property results revealed the presence of a gel-like behavior in emulsions containing 0.5% (w/w) FG. The addition of NaCl destabilized the emulsions by reducing the electrostatic repulsion, which resulted in larger particle size and lower ζ-potential. The salt stability of the emulsions was significantly improved by increasing the amount of FG. Emulsions prepared with 0.5% (w/w) FG were stable under lower NaCl (0–0.4 M) concentrations. Using low-field nuclear magnetic resonance (NMR) spectroscopy, we obtained shorter T2 values in emulsions containing 0.1% (w/w) FG or 0.6 M NaCl. The 1H and 13C high-field NMR spectra showed an increase of line-widths as FG concentration increased and NaCl concentration deceased, which confirmed the increasing interaction between the FG and oil molecules. This study would help to widen the application of flaxseed gum which is insensitive to NaCl, and also contribute to the understanding of gum-lard interaction in emulsion.