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Quantitative analyses of olive oil for lipophilic antioxidants, such as α-tocopherol and phenolics, by simple electrochemical measurements were conducted in a bicontinuous microemulsion (BME), which was bicontinuously composed of saline and toluene microphases with a surfactant system. Lipophilic antioxidants in oils were directly monitored in BME solutions using a lipophilic, fluorinated nanocarbon-film electrode (F-ECR). The combination of a well-balanced BME and extremely biased electrodes, such as strongly hydrophilic indium/tin oxide and strongly lipophilic (hydrophobic) F-ECR, allowed individual monitoring of hydrophilic and lipophilic antioxidants in the same BME solution without any required extraction. Furthermore, values for the charge Q, integrated from observed currents, showed good linear relationships with the results of conventional assays for antioxidant activity, namely, total phenolics and oxygen radical absorbance capacity assays, even with practical food samples. This proposed methodology provided a very simple, rapid, easily serviceable, and highly reproducible analysis that possesses great potential for applications to a wide range of chemical mixtures, in terms of analyte and media, beyond food oils. [ABSTRACT FROM AUTHOR]

Qualitative and quantitative analyses of hydrophilic and lipophilic antioxidants, such as polyphenols, by simple electrochemical measurements were conducted in a bicontinuous microemulsion (BME), in which water and oil phases coexisted bicontinuously on a microscopic scale. Hydrophilic and lipophilic antioxidants were individually monitored in the same BME solution using a hydrophilic indium tin oxide (ITO) electrode and a lipophilic fluorinated nanocarbon film electrode (F-ECR), respectively. The combination of well-balanced BME and extremely biased electrodes, such as ITO and F-ECR, in terms of hydrophilic-lipophilic balance allowed us to achieve individual monitoring of hydrophilic and lipophilic antioxidants in the same BME solution without extraction. Furthermore, the antioxidant activities of functional liquid foods, such as coffee and olive oil, were also evaluated by means of electrochemical measurements in BME solutions containing analytes in concentrations of several percent. The technique we propose provides a very simple, rapid, easily serviceable, and highly reproducible analysis and can be extended to a wide range of analytes and media. [ABSTRACT FROM AUTHOR]

A new class of unique soft gels was produced by gelations of bicontinuous microemulsions (BME). Three alternative composite gel systems, namely BME organogel, hydrogel and an organo/hydro hybrid gel, prepared by hydrogelation and/or organogelation of BME solutions were proposed. These gels were self-supported, and aqueous and oil microphases bicontinuously coexisted and were immobilized in the gels. Even in “one side only” gelation products such as the BME organogel and the BME hydrogel, alternate solvent phases without gelator were also macroscopically immobilized. Microscopic structures of the gels were confirmed by CLSM and SEM observation. The BME organogels or hydrogels and BME hybrid gels showed continuous porous structures and double network structures, respectively. Mesostructures of the gels significantly depended on gelation conditions. It was found that the hierarchical structure of the BME gels was regulated by competition among three synergetic rate factors: immobilization of the BME structure by gelation, mesoscopic phase separation by gelation, and the time-dependent transformation of a solution/solution structure toward a thermodynamic structure in an equilibrium state. [ABSTRACT FROM AUTHOR]