Influence of interfacial characteristics and antioxidant polarity on the chemical stability of β-carotene in emulsions prepared using non-ionic surfactant blends

To evaluate the effects of characteristics of the interfacial region and physical location of antioxidants on the chemical stability of β-carotene in emulsions, β-carotene-loaded emulsions were prepared with the blends of surfactants with different hydrophilic head sizes (ethylene oxide (EO) unit number). In addition, antioxidants having the different solubilities, tert-butylhydroquinone (TBHQ) and lauryl gallate as lipophilic and amphiphilic antioxidants, respectively, were incorporated into emulsions. Decrease in the average EO unit number at interfacial region by surfactant blending did not affect the stability of β-carotene in emulsions at neutral pH but it had a positive effect on the β-carotene stability at acidic pH. Decrease in the average EO unit number at interfacial region reduced the ability of antioxidants, regardless of their polarity, to protect β-carotene in emulsions at neutral and acidic pH. TBHQ was more effective in retarding β-carotene degradation than lauryl gallate, independent of the interfacial composition and surfactant concentration.