title: Antioxidant activity of alkyl gallates and glycosyl alkyl gallates in fish oil in water emulsions: relevance of their surface active properties and of the type of emulsifier.
abstract: The antioxidant activity of gallic acid and a series of alkyl gallates (C4-C18) and glycosylated alkyl gallates (C4-C18) on fish oil-in-water emulsions was studied. Three types of emulsifiers, lecithin, Tween-20 and sodium dodecyl sulphate (SDS) were tested. A nonlinear behavior of the antioxidant activity of alkyl gallates when increasing alkyl chain length was observed for emulsions prepared with lecithin. Medium-size alkyl gallates (C6-C12) were the best antioxidants. In contrast, for emulsions prepared with Tween-20, the antioxidants seem to follow the polar paradox. Glucosyl alkyl gallates were shown previously to be better surfactants than alkyl gallates. Nevertheless, they exhibited a worse antioxidant capacity than their corresponding alkyl gallates, in emulsions prepared with lecithin or Tween-20, indicating the greater relevance of having three OH groups at the polar head in comparison with having improved surfactant properties but just a di-ortho phenolic structure in the antioxidant.
authors: Instituto de Investigaciones Marinas, CSIC, 6 Eduardo Cabello, 36208 Vigo, Spain.
authors: María J
authors: MJ
authors: González
authors: Instituto de Investigaciones Marinas, CSIC, 6 Eduardo Cabello, 36208 Vigo, Spain.
authors: Isabel
authors: I
authors: Medina
authors: Instituto de Investigaciones Químicas, CSIC - Universidad de Sevilla, 49 Americo Vespucio, 41092 Sevilla, Spain.
authors: Olivia S
authors: OS
authors: Maldonado
authors: Instituto de Investigaciones Químicas, CSIC - Universidad de Sevilla, 49 Americo Vespucio, 41092 Sevilla, Spain.
authors: Ricardo
authors: R
authors: Lucas
authors: Instituto de Investigaciones Químicas, CSIC - Universidad de Sevilla, 49 Americo Vespucio, 41092 Sevilla, Spain. Electronic address: jcmorales@iiq.csic.es.
authors: Juan C
authors: JC
authors: Morales
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D045703:Emulsifying Agents / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry*; D005395:Fish Oils / Q000737:chemistry*; D005707:Gallic Acid / Q000737:chemistry*; D006031:Glycosylation; D054709:Lecithins; D010084:Oxidation-Reduction; D013501:Surface-Active Agents / Q000737:chemistry; D014867:Water
chemical_list: D000975:Antioxidants; D045703:Emulsifying Agents; D004655:Emulsions; D005395:Fish Oils; D054709:Lecithins; D013501:Surface-Active Agents; D014867:Water; D005707:Gallic Acid
keywords: Alkyl gallates; Antioxidant; Gallic acid; Glycosylation; Lipid oxidation; Oil-in-water emulsions; Surfactant