Direct Analysis of Lipophilic Antioxidants of Olive Oils Using Bicontinuous Microemulsions

Abstract

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.

Protein-olive oil-in-water nanoemulsions as encapsulation materials for curcumin acting as anticancer agent towards MDA-MB-231 cells

“…of rotation without any cosurfactant. Moreover, unlike the previously published reports [50][51][52][53][54] . we have also presented first visual evidence (TEM image) of olive oil sitting in the micellar cavity of the surfactant, PF 127 (Fig.…”

“…Although olive oil has been extensively used as water in oil microemulsion (W/O) for various applications, there are few reports of its utility as oil in water (O/W) micro/ nanoemulsion [50][51][52][53][54] . These microemulsion were prepared using either co-surfactants or a number of chemical stabilizers using highly energy intensive procedures like ultrasonication and temperature induced phase inversion etc.…”

Hybrid Carbon Film Electrodes for Electroanalysis

“…4 B while maintaining sufficient electrochemical activity for FcPMB. (vitamin E) in olive oil samples by using a bicontinuous microemulsion (BME) solution and can selectively detect lipophilic vitamin E 60,61 with no interference of L-ascorbic acid which is a well-known hydrophilic antioxidant.…”

Lipophilic probe behavior in microemulsions evaluated by fluorescence correlation spectroscopy

“…Indeed, Kuraya et al reported the selective and individual determination of hydrophilic and lipophilic antioxidants in the same BME solution. 11,12 Here, a hydrophobic fluorinated nanocarbon (F-nanocarbon) film electrode produced the oxidation current of lipophilic α-tocopherol (vitamin E, VE), but no oxidation peak for hydrophilic L-ascorbic acid (vitamin C, VC). In contrast, hydrophilic indium tin oxide electrode exhibited the oxidation response of VC but not of VE.…”