Effect of Surfactants on Kinetics of β-carotene Photodegradation in Emulsions

The effect of surfactant type on photodegradation kinetics of beta-carotene in oil-in-water emulsions has been investigated. The stabilized emulsions of lecithin, sodium stearoyl 2-lactylate (SSL), and polyoxyethylene sorbitan monolaurate (Tween-20) together with a beta-carotene solution in corn oil were exposed to illumination. The rate of photochemical degradation was mathematically modeled by regression fitting. The lecithin-stabilized emulsion showed higher light fastness than the other samples. beta-carotene photodegradation reaction followed a zero-order kinetic model for oil-based systems and lecithin emulsions, while beta-carotene degraded by a first-order reaction in SSL and Tween-20 emulsions. Thermodynamic parameters revealed that water-based samples are more heat sensitive than oil-based samples. An isokinetic relationship was observed between the samples. Moreover, results indicated mixing of SSL and Tween-20 with lecithin leads to better protection of beta-carotene than emulsions stabilized with SSL or Tween-20, separately.