Polar paradox revisited: analogous pairs of hydrophilic and lipophilic antioxidants in linoleic acid emulsion containing Cu(<scp>II</scp>)

Bakır, Temelkan; Sönmezoğlu, İnci; İmer, Filiz; Apak, Reşat

doi:10.1002/jsfa.6063

Cited by 13 publications

(13 citation statements)

References 39 publications

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“…However, there are conditions in which the “polar paradox” cannot be applied. Bakir et al reported that “polar paradox” experiences are limited in O/W emulsions and that its validity also depends on the concentrations of the antioxidants used in the study . They noted that antioxidants with different polarity accumulate up to a critical concentration at the interfaces of emulsion droplets, thereby obeying the “polar paradox” hypothesis.…”

Section: Introductionmentioning

confidence: 99%

Vitamin E: Regulatory Redox Interactions

et al. 2019

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Vitamin E is an essential nutrient that was discovered in the 1920s. Many of the physiological functions of vitamin E, including its antioxidative effects, have been studied for nearly 100 years. Changes in redox balance induced by both endogenously and exogenously generated reactive oxygen species (ROS) are involved in various diseases, and are also a phenomenon that is considered essential for survival. Vitamin E is known to regulate redox balance in the body due to its high concentration among the lipid soluble vitamin groups, and exists ubiquitously in the whole body, including cell membranes and lipoproteins. However, it has been reported that the beneficial properties of vitamin E, including its antioxidative effects, are only displayed in vitro, and not in vivo. Therefore, there exists an ongoing debate regarding the biological functions of vitamin E and its relationship with redox balance. In this review, we introduce the relationship between vitamin E and redox interactions with (i) absorption, distribution, metabolism, and excretion of vitamin E, (ii) oxidative stress and ROS in the body, (iii) mechanism of antioxidative effects, (iv) non‐antioxidant functions of vitamin E, and (v) recent recognition of the field of oxidative stress research. Understanding the recent findings of the redox interaction of vitamin E may help to elucidate the different antioxidative phenomena observed for vitamin E in vitro and in vivo. © 2019 IUBMB Life, 71(4):430–441, 2019

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Section: Introductionmentioning

confidence: 99%

Vitamin E: Regulatory Redox Interactions

et al. 2019

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“…To investigate the effect of catalytic metal ions, Cu 2+ and Co 2+ ions were selected to study their potential to accelerate LA oxidation in the emulsion system. Copper(II) ions were chosen because of their reported strong prooxidant effect [16], and also since they are present in biological systems, while Co 2+ ions have been reported to be powerful oxidising agents [31].…”

Section: Resultsmentioning

confidence: 99%

“…Aqueous solutions (0.05 M) of copper(II) chloride and cobalt(II) chloride were prepared and 1 mM was used as the final concentration in the oxidation mixture [16,22]. For the oxygen initiator (Fe 2+ + hydrogen peroxide), 3 µM iron(II) chloride and 2 µM hydrogen peroxide solutions were prepared separately, from which 0.04 µM Fe 2+ and 0.01 µM hydrogen peroxide were used as the final concentrations [23].…”

Section: Methodsmentioning

confidence: 99%

“…Using an LA emulsion, there are a number of reports where oxidation was conducted at 37 °C, with FTC [8], TBARS [15] or both assays [16]. With these studies, the choice of 37 °C was due to the fact that it is a physiologically relevant temperature, and it is important to use conditions as close as possible to those in which physiological oxidation occurs [17].…”

Section: Introductionmentioning

confidence: 99%

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Development of a Method Suitable for High-Throughput Screening to Measure Antioxidant Activity in a Linoleic Acid Emulsion

et al. 2019

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An improved system for measuring antioxidant activity via thiobarbituric acid reactive substances and ferric thiocyanate assays is reported, on the basis of oxidation of a linoleic acid (LA) emulsion. Oxidation times were reduced from 20 h to 5 h by increasing the reaction temperature from 37 °C to 50 °C and with an acceptable precision of <10% coefficient of variation (CV). Antioxidants varying in polarity and chemical class—250 µM Trolox, quercetin, ascorbic acid and gallic acid—were used for method optimisation. Further reductions in reaction time were investigated through the addition of catalysts, oxygen initiators or increasing temperature to 60 °C; however, antioxidant activity varied from that established at 37 °C and 20 h reaction time—the method validation conditions. Further validation of the method was achieved with catechin, epicatechin, caffeic acid and α-tocopherol, with results at 50 °C and 5 h comparable to those at 37 °C and 20 h. The improved assay has the potential to rapidly screen antioxidants of various polarities, thus making it useful in studies where large numbers of plant extracts require testing. Furthermore, as this assay involves protection of a lipid, the assay is likely to provide complementary information to well-established tests, such as the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.

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“…Additionally, regarding TBARS assay, it has been reported that in general, TBARS values did not vary distinctly with antioxidant concentration, and showed rather low sensitivity and selectivity (Bakır et al . ). In the same context, because color represents one of the first acceptance attributes evaluated by consumer, it is crucial to consider the possible impact on sensorial attributes of the products incorporating the MDM as association between red‐pink color and “under cooked” product would be assumed.…”

Section: Discussionmentioning

confidence: 97%

Effect of Touriga nacional Grape Extract on Characteristics of Mechanically Deboned Chicken Meat Kept Under Frozen Storage

Tournour

Segundo

Magalhães

et al. 2016

J Food Process Engineering

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Grape pomace extract (GPE) is a by-product from the wine industry that is rich in bioactive compounds. The effect of Touriga nacional GPE on quality characteristics (composition, pH, color variables and antioxidant capacity) of mechanically deboned chicken meat (MDM) under frozen storage was evaluated. Two MDM samples with different compositions fortified with two levels of GPE (60 and 120 mg/kg) were tested and analyzed within 1 and 210 days of storage. Data obtained was evaluated by principal component analysis (PCA) and the first two PCs accounted for 85% of the total variability. PC1 (47.9%) was positively correlated with a* (redness) and chroma, while negatively correlated with antioxidant indexes. PC2 (36.7%) was positively correlated with b* (yellowness) and Hue angle, and likewise PC1 negatively correlated with antioxidant properties. In conclusion, the addition of GPE to MDM is feasible to maintain the antioxidant properties and contributes positively to MDM color attributes over frozen storage, even using MDM batches with different proximal composition. PRACTICAL APPLICATIONSThis research targets two practical applications. First, it highlights the use of grape pomace extract as a sustainable source of bioactive compounds, namely antioxidants, as grape pomace is a by-product from the wine industry. Second, it demonstrates that the quality of mechanically deboned chicken meat under frozen storage can be maintained after grape pomace addition. Future incorporation of mechanically deboned chicken meat supplemented with grape pomace extract in comminuted products is envisioned.

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Polar paradox revisited: analogous pairs of hydrophilic and lipophilic antioxidants in linoleic acid emulsion containing Cu(II)

Abstract: The results of this study partly confirm the hypothesis that the polar paradox experiences limitations in oil-in-water emulsions and that its validity is also dependent on the concentrations of the antioxidants employed.

Cited by 13 publications

References 39 publications

Vitamin E: Regulatory Redox Interactions

Vitamin E: Regulatory Redox Interactions

Development of a Method Suitable for High-Throughput Screening to Measure Antioxidant Activity in a Linoleic Acid Emulsion

Effect of Touriga nacional Grape Extract on Characteristics of Mechanically Deboned Chicken Meat Kept Under Frozen Storage

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