Mesquite seed gum and palm fruit oil emulsion edible films: influence of oil content and sonication

Abstract

Mesquite seed gum (MSG) was extracted and confirmed as a galactomannan, presenting a galactose/ mannose (G/M) ratio of about 1:1.1. Emulsions of MSG and palm fruit oil (PFO) were prepared by mixing a PFO nanoemulsion with MSG and glycerol, in order to obtain MSG/PFO emulsion films by casting and evaporation. The influence of sonication time of O/W nanoemulsion and PFO content (based on MSG) on the film properties were evaluated. All O/W emulsions presented nanosized droplets, lower PFO contents producing smaller droplets. Increasing PFO contents resulted in increased hydrophobicity (reflected as increased water contact angles, decreased water solubility and water vapor permeability), and impaired transparency and tensile properties (except for elongation). The only significant effects of sonication were the increase of film hydrophilicity (decreasing contact angles) and improvement of tensile strength, probably by promoting a more uniform droplet dispersion.