Peroxidase-mediated conjugation of corn fiber gum and bovine serum albumin to improve emulsifying properties

• Peroxidase catalyzes hetero- and homo-conjugation of CFG and BSA.
• Hetero-conjugation is favored when CFG is in large excess over BSA.
• Conjugates exhibit better emulsifying abilities under freeze–thawing.

The emulsifying properties of corn fiber gum (CFG), a naturally occurring polysaccharide–protein complex, was improved by kinetically controlled formation of hetero-covalent linkages with bovine serum albumin (BSA), using horseradish peroxidase (HRP). The formation of hetero-crosslinked CFG–BSA conjugates was confirmed using ultraviolet–visible and Fourier-transform infrared analyses. The optimum CFG–BSA conjugates were prepared at a CFG:BSA weight ratio of 10:1, and peroxidase:BSA weight ratio of 1:4000. Selected CFG–BSA conjugates were used to prepare oil-in-water emulsions; the emulsifying properties were better than those of emulsions stabilized with only CFG or BSA. Measurements of mean droplet sizes and zeta potentials showed that CFG–BSA-conjugate-stabilized emulsions were less susceptible to environmental stresses, such as pH changes, high K ionic strengths, and freeze–thaw treatments than CFG- or BSA-stabilized emulsions. These conjugates have potential applications as novel emulsifiers in food industry.