Effects of milk protein-polysaccharide interactions on the stability of ice cream mix model systems

Polysaccharides (PS) are commonly used as stabilizers in ice cream to improve the structural and textural properties. However, in emulsions, the polysaccharides can interact with the milk proteins, resulting in the thermodynamic destabilization of the emulsion systems. This paper focuses on the effect of the interactions between milk proteins and two gums (carboxymethylcellulose (CMC) and guar gum (GG)) on the stability of ice cream models consisting of 11% skimmed milk powder (SMP) and 10% coconut oil. Parameters such as interfacial tension, fluorescence spectroscopy, zeta-potential, surface adsorption, microstructure, creaming, and rheological properties were determined. Furthermore, the interactions between the proteins and PS attributed to the stability of the emulsions were characterized. The results indicated that the stability of ice cream model emulsions depended on the types and concentrations of polysaccharides. SMP/GG mixed emulsions were distinguished by a higher rate of creaming compared to SMP/CMC mixed models with the same levels of polysaccharides (except for 0.1%). Depletion flocculation was involved in the destabilization of the two SMP/PS emulsion systems. Lower creaming rates above the critical content of phase separation in the SMP/CMC mixed models were related to the attractive interactions between milk proteins and CMC and enhanced apparent viscosity compared to that of SMP/GG systems. These findings provided a theoretical basis for ice cream processing; however, further research is required due to the complex ingredients and reactions involved during ice cream processing. (C) 2015 Elsevier Ltd. All rights reserved.