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.