Cross-linking of interfacial layers affects the salt and temperature stability of multilayered emulsions consisting of fish gelatin and sugar beet pectin.

This study assessed the stabilizing effect of enzymatic cross-linking on double-coated emulsions (beet pectin-fish gelatin). The beet pectin layer was cross-linked via ferulic acid groups using laccase (an enzyme that is known to catalyze the oxidation of phenolic groups). Fish gelatin-coated oil droplets (primary emulsion) were mixed at pH 3.5 to promote electrostatic deposition of the beet pectin molecules onto the surfaces of the oil droplets (secondary emulsion). Laccase was then added to promote cross-linking of the adsorbed beet pectin layer. Cross-linked pectin-coated oil droplets had similar or significantly better stability (p < 0.05) than oil droplets of primary or secondary emulsions to NaCl addition (0-500 mM), CaCl(2) addition (0-250 mM), and thermal processing (30-90 °C for 30 min). Freeze-thaw stability and creaming behavior of enzyme-treated, secondary emulsions after two cycles (-8 °C for 22 h; 25 °C for 2 h) were significantly improved (p < 0.05). These results may have important implications for food manufacturers that are in need of emulsions with improved physical stability, for example, emulsions used in frozen foods for sauces or dips.