Antioxidant activity of a Maillard-type phosvitin-galactomannan conjugate with emulsifying properties and heat stability

摘要

Egg yolk phosvitin was conjugated with galactomannan through a controlled Maillard reaction at 60 degrees C in 79% relative humidity for 1 week. Antioxidant activity of phosvitin and phosvitin-galactomannan conjugate (PGC) was assessed using a powdered model linoleic acid system. The conjugation reaction significantly (P < 0.05) enhanced the antioxidant activity of phosvitin. One-tenth percent PGC suppressed the relative lipid oxidation rate catalyzed with 1 mg/L Fe2+ to 75% and 73% in thiobarbituric acid and peroxide values, respectively, compared to those of a simple phosvitin-galactomannan mixture after 3 days at 20 degrees C. The antioxidant effect of PGC was not affected by autoclaving (121 degrees C, 1.2 atm for 15 min), whereas the same treatment when applied to native phosvitin resulted in a lower affinity to inhibit iron-catalyzed lipid oxidation. The conjugation of phosvitin with galactomannan significantly (P < 0.05) improved both emulsifying activity and emulsion stability. The results demonstrate that the Maillard-type PGC can be used as an effective macromolecular antioxidant, with good emulsifying properties and heat stability. [References: 31]