Application and evaluation of mesquite gum and its fractions as interfacial film formers and emulsifiers of orange peel-oil

Mesquite gum was fractionated using hydrophobic interaction chromatography, yielding three fractions (F₁, F₂, F₃) whose average molecular masses ranged from 1.81 × 10⁴ to 5.23 × 10⁵ Da; F₁ had 90% polysaccharide and 1% protein contents, while F₂ and F₃ contained 16 and 46% of protein, respectively. Fractions' ability to form oil–water interfacial films and to stabilize orange peel–oil emulsions was evaluated. The highest interfacial viscosity (321 m Nm⁻¹) and highest instantaneous elastic modulus (E₀) = 0.113 × 10⁻⁴ m Nm⁻¹ were exhibited by F₂ and these values were significantly higher than those exhibited by the whole mesquite gum. F₁ did not exhibit viscoelastic properties. Emulsions made with F₂, F₃, and the whole mesquite gum had coalescence rates of the order of 10⁻⁸ s⁻¹, indicating that these emulsions were very stable. Nevertheless, emulsions made with F₂ were significantly more stable than those made with F₃ and whole mesquite gum, and emulsions made with F₁ broke after 1 day aging. These results indicate that there is a close correlation between emulsion stability, interfacial rheological properties, and an adequate relatively high protein/high polysaccharide balance in the fractions.