Impact of backbone stiffness and hydrophobic chain length of modified xanthan on oil in water emulsion stabilization.

• The effect of alkyl grafted xanthan derivatives chain stiffness on the stabilization on O/W emulsions was investigated. • A series of xanthan hydrophobic derivatives was prepared under ordered and disordered conformation • Stiff Hydrophobically Modified Xanthan permitted long term stabilization of emulsions with flexible ones did not. • Amphiphilic xanthan under disordered conformation stabilizes O/W emulsion when alkyl length brings gel-like viscoelastic properties • The Oil-in-Water emulsions stabilization by Hydrophobically Modified Xanthan is mainly governed by aqueous continuous phase rheology The impact of xanthan chemical modification under both ordered and disordered conformations on oil-in-water (O/W) emulsion stabilization was investigated. While both hydrophobically modified xanthan (HMX) are able to stabilize the O/W interface, a dramatic difference was observed macroscopically. When HMX ord (ordered conformation) could produce stable emulsions at concentrations down to 0.2% w/w, HMX dis (disordered conformation) led to unstable systems mostly by creaming whatever the concentration studied. Moreover, in the case of HMX dis , the role of the grafted chain length was investigated and two different behaviors were observed depending on the grafting unit. It was demonstrated that the cornerstone of these emulsion stability was the rheological properties of the continuous phase which was governed by two main factors: the partitioning of HMX dis between the interface and the continuous phase and the viscosifying ability of the polymer, the latter being directly linked to the backbone stiffness. [ABSTRACT FROM AUTHOR]