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 (F-1, F-2, F-3) whose average molecular masses ranged from 1.81 x 10(4) to 5.23 x 10(5) Da; F-1 had 90% polysaccharide and 1% protein contents, while F-2 and F-3 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 (E-0) = 0.113 x 10(-4) m Nm(-1) were exhibited by F-2 and these values were significantly higher than those exhibited by the whole mesquite gum. F, did not exhibit viscoelastic properties. Emulsions made with F-2, F-3, 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 F-2 were significantly more stable than those made with F-3 and whole mesquite gum, and emulsions made with F-1 broke after 1 day aging. These results indicate that there is a close correlation between emulsion stability, interfacial theological properties, and an adequate relatively high protein/high polysaccharide balance in the fractions. (C) 2008 Elsevier Ltd. All rights reserved.