Ability of Sodium Dodecyl Sulfate (SDS) Micelles to Increase the Antioxidant Activity of α-Tocopherol.

As emulsifiers become saturated on the surface of an emulsion droplet, any additional emulsifier migrates to the aqueous phase. Continuous phase surfactants have been shown to increase α-tocopherol efficacy, but it is unclear if this is the result of chemical or physical effects. The addition of α-tocopherol to an oil-in-water emulsion after homogenization resulted in a 70% increase of α-tocopherol in the continuous phase when sodium dodecyl sulfate (SDS) was at levels that were greater than the SDS critical micelle concentration. Conversely, when α-tocopherol was dissolved in the lipid before emulsification, continuous phase SDS concentrations did not increase. When SDS concentration led to an increase in the aqueous phase α-tocopherol, the oxidative stability of oil-in-water emulsions increased. Data indicated that the increased antioxidant activity was the result of surfactant micelles being able to decrease the prooxidant activity of α-tocopherol. Considering these results, surfactant micelles could be an important tool to increase the effectiveness of α-tocopherol.

Phthalates levels in olive oils and olive pomace oils marketed in Turkey.

Phthalates are used as additives and plasticisers in packaging for personal care and food products. Several investigations reported the harmful impact of phthalates on human health. In this study, different types of olive oils (12 olive oil; 20 extra virgin oil; 4 refined pomace oil) in different packaging materials [polyethylene terephthalate (PET), glass and metal] obtained from local markets in Turkey in 2019, were analysed using GC-MS for the presence of benzyl butyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), and diisodecyl phthalate (DIDP). The average recoveries of the 5 phthalates in olive oils were 87%-100%, with limits of quantification (LOQs) of 0.09-2.28 mg/kg. DEHP was the abundant phthalate in all olive oil samples ranging from below the LOQ (0.23 mg/kg) to 602 mg/kg. In all analysed samples, the levels of DINP and DIDP were less than their LOQ, thus these phthalates were not detected. The highest DEHP content was found in an olive oil sample containing 602 mg/kg, whilst 5 samples did not contain detectable phthalate esters.

Reducing polycyclic aromatic hydrocarbons (PAHs) in olive pomace oil using short-path molecular distillation.

Bleached olive pomace oil (BOPO) was distilled using a short-path molecular distillation unit to determine the impacts of distillation conditions on the removal of 15 PAHs from the list of 16 EPA-priority pollutant PAHs. The removal of PAHs was achieved at elevated temperatures (110-230°C) and pressures (0.05, 0.5, 5 mbar). The oil was also deodorised at 230°C under 0.5, 1 and 5 mbar pressures to determine the effect of pressure during deodorisation on the removal of PAHs. High-performance liquid chromatography (HPLC) with fluorescence detector (HPLC-FLD) was used for quantifying PAH concentrations in oil samples. PAH concentrations in BOPO were considerably reduced after molecular distillation and both temperature increment and pressure decrease were effective for the removal of PAHs from olive pomace oil. When above 190°C, BaP could be reduced to <2 µg/kg at all pressures. Distillation at 230°C under 0.05 mbar absolute pressure reduced the sum of four PAHs (BaP, Chr, BaA, BbF) to 7 µg/kg, which meets the acceptable levels established by the European Union (10 µg/kg). Deodorisation effectiveness was increased by decreasing absolute pressure, particularly for light PAHs.

Increased antioxidant efficacy of tocopherols by surfactant solubilization in oil-in-water emulsions.

The physical location of antioxidants in oil-in-water emulsions can have significant influence on their free radical scavenging activity and ability to inhibit lipid oxidation. We aimed to determine the effect of the surfactant concentration on the partitioning behavior of tocopherols (α, γ, and δ) in oil-in-water emulsions. Tween 20 (0.1, 0.5, and 1%) increased the partitioning of the tocopherols into the aqueous phase via the formation of Tween 20-tocopherol comicelles. Partitioning behavior of antioxidants was dependent upon the number of methyl groups and, thus, polarity of the tocopherols. δ-Tocopherol (one methyl group) exhibited the most partitioning into the aqueous phase, while α-tocopherol (three methyl groups) had the lowest partitioning. Lipid oxidation studies showed that the antioxidant activity of δ- and α-tocopherols was enhanced by adding Tween 20 to oil-in-water emulsions. This work suggests that surfactant micelles could increase the antioxidant activity of tocopherols by changing their physical location.