The fatty acid composition, total phenol content and tocopherol content of olive oils from Shodo Island of Japan were analyzed for di#erent varieties, maturation stages and extraction methods. Radicalscavenging activity of olive oils was also determined spectrophotometrically by measuring the disappearance of +,+-diphenyl-,-picrylhydrazyl radical at /+1 nm. The di#erences in fatty acids composition, total phenol and tocopherol content in virgin olive oils were not great among the varieties. The content of oleic acid was in range of 00ῌ12ῌ. Though virgin olive oils contained more phenolic compounds than hexaneextracted olive oils, tocophenol content was not very di#erent. In hexane-extracted olive oils, the total phenol content decreased during olive maturation. The tocopherol content of three types of olive oils also decreased during maturation. Still, large amounts of phenolic compounds remained in the olive residue after hexane extraction. The contribution of tocopherols to radical-scavenging activity was -3ῌ0+ῌ in virgin olive oil, which suggests that both tocopherols and phenolic compounds contribute to radicalscavenging activity.

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Abstract. The emulsification properties and emulsion stability of polyphenols on vegetable oils were investigated. Vegetable oil is always processed into foods existing as emulsions. In this study the author used edible oil-in-water emulsions stabilized by soya protein isolate (SPI) to investigate the differences between the emulsifying ability and stability of protein-stabilized emulsions. The author also investigated the interfacial activity of the edible oils, aglycon and glucoside of phenolic compound. From the results, virgin olive oil existed better emulsifying ability and stability than the other edible oils. Phenolic content, especially aglycon and glycoside compounds in olive oil were expected to responsible for the emulsification activity and emulsion stability of olive oil.