Natural antioxidants from residual sources.

Antioxidant activity of selected essential oil components in two lipid model systems

https://bib.irb.hr/datoteka/145388.29.pdf

Use of different methods for testing antioxidative activity of oregano essential oil

Identification of volatile components in basil Ocimum basilicum L and thyme leaves Thymus vulgaris L and their antioxidant properties

Effect of chitosan coatings enriched with cinnamon oil on the quality of refrigerated rainbow trout

Antioxidant activity and mechanism of action of thymol and carvacrol in two lipid systems

The relevant recent literature regarding the antioxidant properties of β-carotene as a radical scavenger and singlet oxygen quencher in lipid oxidation is presented and discussed. In this connection, a brief information about the biological activity of β-carotene is also given. As the antioxidative behaviour of β-carotene is closely related to its own oxidation, the rate and mechanism of oxidative degradation of β-carotene at different conditions are also presented. Taking into account the results of the papers discussed in this review, further investigations of the cooperative action of β-carotene with other natural antioxidants, e.g., non-toxic flavonoids, phenolic acids, coumarins, etc., should be carried out. This is recommended in view to obtain new types of edible fats and lipid containing products with high oxidation stability, which, at the same time, could serve as functional foods with positive effects on our nutrition and health.



β-Carotin und Lipidoxidation



Die relevante neuere Literatur betreffend der Eigenschaften von β-Carotin als Antioxidans, Radikalfanger und als Quencher' von Singulettsauerstoff im Zusammenhang mit der Oxidation von Fetten wird vorgestellt und kurz diskutiert. Eine kurze Information uber die biologische Aktivitat von β-Carotin wird in diesem Zusammenhang ebenfalls gegeben. Weil das antioxidative Verhalten von β-Carotin eng mit seiner eigenen Oxidation zusammenhangt, werden auch die Raten und Mechanismen des oxidativen Abbaus von β-Carotin unter unterschiedlichen Bedingungen beschrieben. Wenn man die Ergebnisse der in dieser Ubersichtsarbeit diskutierten Veroffentlichungen berucksichtigt, dann kommt man zu dem Schlus, das weitere Untersuchungen uber das Zusammenwirken von β-Carotin mit anderen naturlichen Antioxidantien (z. B. nichttoxische Flavonoide, Phenolsauren, Coumarine etc.) durchgefuhrt werden sollten. Dies wird empfohlen, um neue Arten von Speisefetten und fetthaltigen Lebensmitteln mit hoher Oxidationsstabilitat zu erhalten, die gleichzeitig auch als “Functional Foods” mit positiven Effekten zu unserer Ernahrung und Gesundheit beitragen konnten.

β‐Carotene and lipid oxidation

The oxidation kinetics of sunflower oil (SO), as well as of pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.001-0.02 %) β-carotene was studied. The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature in the dark and under daylight. The results from the oxidation of SO and TGSO at 100oC in the presence of β-carotene were also presented. It was established that in the antioxidant-free lipid system, the β-carotene did not give any antioxidative protection. It worked as a prooxidant during the oxidation at room temperature and at sufficiently high oxygen concentration, the effect being more pronounced in the dark than under daylight. β-carotene increased the stability of tocopherol-containing SO during its oxidation at room temperature and under daylight. This effect is more strongly expressed in a kinetic regime of oxidation. The synergism of β-carotene with the tocopherols was characterized by the stabilization factor F and the activity A. In the kinetic regime of oxidation F and A varied in the interval F=2.0-6.3, and A =2.7-21.0. In the diffusion regime F=1.3-1.5, and A=1.5-2.8.

/pdf/b-carotene-in-sunflower-oil-oxidation-6f06e0u0qe.pdf

β-carotene in sunflower oil oxidation

The oxidation kinetics of sunflower oil (SO) and pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (00008–002%, 19–327×10−5 M) of β-apo-8′-carotenoic acid (CA), ethyl β-apo-8′-carotenoate (EC), and β-apo-8′-carotenoylglycerol (CG) were studied The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature and at 100°C and in the dark and in daylight CA, EC, and CG were not antioxidants in TGSO systems However, the carotenoid derivatives, especially CA, increased the stability of tocopherol-containing SO at room temperature and in daylight The stabilization effect was more evident in a kinetic regime of oxidation The synergism between the carotenoids and tocopherols was characterized by the increase of the stabilization factor F and activity A F and A were highest for CA (F=12–55, A=24–786), followed by EC (F=12–35, A=17–146) and CG (F=11–21, A=16–55) in the kinetic regime for SO exposed to daylight at room temperature

β-Apo-8′-Carotenoic acid and its esters in sunflower oil oxidation

The effect of 11-selenadodecylglyceryl-1-ether (11-SeDGE) at concentrations of 5 × 10−4 and 1 × 10−2 M on the autoxidation of sunflower oil with a natural content of 0.06% tocopherols at 100°C and at room temperature in the dark and of pure triacylglycerols of sunflower oil (TGSO) at 100°C was studied. The process was followed by peroxide concentration (peroxide value) determination and by ultraviolet (UV) spectroscopy. It was found that 11-SeDGE acted synergistically with the tocopherols in sunflower oil in a dose-dependent manner to delay oxidation at 100°C. The results from the UV spectra indicated that 11-SeDGE decomposed the initiators of the process, the hydroperoxides, into inactive products. During oxidation of pure TGSO (i.e, depleted of tocopherols) at 100°C, 11-SeDGE retarded the process without a pronounced induction period. At room temperature, 11-SeDGE showed a slight prooxidative effect on sunflower oil oxidation. Taking into account the established prooxidative effect of the two hydroxy groups in a molecule such as 11-SeDGE, it was recommended to study the lipid autoxidation in the presence of selenium compounds that do not contain such prooxidative groups.

V. G. Raneva

Papers

Antioxidant activity and mechanism of action of thymol and carvacrol in two lipid systems

β‐Carotene and lipid oxidation

β-carotene in sunflower oil oxidation

β-Apo-8′-Carotenoic acid and its esters in sunflower oil oxidation

11‐selenadodecylglyceryl‐1‐ether in lipid autoxidation