Utjecaj mikrovalnog zagrijavanja i dodatka antioksidansa na održivost ekstra djevičanskog maslinovog ulja sorte Oblica

Virgin olive oil has a high resistance to oxidative deterioration due to both a triacylglycerol composition low in polyunsaturated fatty acids and a group of phenolic antioxidants composed mainly of polyphenols and tocopherols. This essay discusses the effect of microwave heating on the oxidative stability of extra virgin olive oil with or without the addition of antioxidants and synergists. Of natural antioxidants are used rosemary extract and green tea extract and citric acid synergist. Oil samples with or without the addition of antioxidants and synergists were heated in a microwave oven at a constant power of 300 W over a different time period (5, 10, 15 and 20 minutes). Samples were also heated at different power levels (180, 300, 450W) in a constant time period of 5 minutes. The result of the accelerated oxidation test of olive oil is expressed by the peroxide number. Microwave heating of the samples during a longer heating time increases the temperature and the value of the peroxide number, which results in an increase in oxidative oil degradation. Addition of antioxidants and synergists increased the stability of olive oil. The highest stability of extra virgin olive oil was achieved by a combination of green tea extract and synergistic citric acid.

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Ingredient-Dependent Extent of Lipid Oxidation in Margarine

Antioxidants ◽

10.3390/antiox10010105 ◽

2021 ◽

Vol 10 (1) ◽

pp. 105

Author(s):

Sarah Fruehwirth ◽

Sandra Egger ◽

Dennis Kurzbach ◽

Jakob Windisch ◽

Franz Jirsa ◽

...

Keyword(s):

Citric Acid ◽

Lipid Oxidation ◽

Oxidative Stability ◽

Green Tea ◽

Acyl Chain ◽

Green Tea Extract ◽

Tocopheryl Acetate ◽

Tea Extract ◽

The Impact ◽

Β Carotene

This study reports the impact of margarine-representative ingredients on its oxidative stability and green tea extract as a promising antioxidant in margarine. Oil-in-water emulsions received much attention regarding factors that influence their oxidative stability, however, water-in-oil emulsions have only been scarcely investigated. Margarine, a widely consumed water-in-oil emulsion, consists of 80–90% fat and is thermally treated when used for baking. As different types of margarine contain varying additives, their impact on the oxidative stability of margarine during processing is of pressing importance. Thus, the influence of different ingredients, such as emulsifiers, antioxidants, citric acid, β-carotene and NaCl on the oxidative stability of margarine, heated at 80 °C for 1 h to accelerate lipid oxidation, was analyzed by the peroxide value and oxidation induction time. We found that monoglycerides influenced lipid oxidation depending on their fatty acyl chain. α-Tocopheryl acetate promoted lipid oxidation, while rosemary and green tea extract led to the opposite. Whereas green tea extract alone showed the most prominent antioxidant effect, combinations of green tea extract with citric acid, β-carotene or NaCl increased lipid oxidation in margarine. Complementary, NMR data suggested that polyphenols in green tea extracts might decrease lipid mobility at the surface of the water droplets, which might lead to chelating of transition metals at the interface and decreasing lipid oxidation.

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Can tea extracts protect extra virgin olive oil from oxidation during microwave heating?

Food Research International ◽

10.1016/j.foodres.2012.03.005 ◽

2012 ◽

Vol 48 (1) ◽

pp. 148-154 ◽

Cited By ~ 24

Author(s):

Ricardo Malheiro ◽

Susana Casal ◽

Hugo Lamas ◽

Albino Bento ◽

José Alberto Pereira

Keyword(s):

Olive Oil ◽

Microwave Heating ◽

Virgin Olive Oil ◽

Extra Virgin Olive Oil

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Iron Oxide Nanoparticles Synthesized via Green Tea Extract for Doxorubicin Delivery

Current Nanoscience ◽

10.2174/1573413716999201029205654 ◽

2020 ◽

Vol 16 ◽

Author(s):

Lei Nie ◽

Chenlei Cai ◽

Meng Sun ◽

Fang Zhang ◽

Lingyun Zheng ◽

...

Keyword(s):

Iron Oxide ◽

Citric Acid ◽

Iron Oxide Nanoparticles ◽

Green Tea ◽

Drug Carrier ◽

Green Tea Extract ◽

Cancer Drug ◽

Control Group ◽

Oxide Nanoparticles ◽

Tea Extract

Background:: Due to the limitation of conventional cancer treatment using chemotherapy, the nanoparticle therapeutics showed enhanced efficacy with alleviating side effects. Objective:: The superparamagnetic iron oxide nanoparticles (T-C-SPION) would be prepared for doxorubicin (DOX) loading and delivery. Methods:: Here, we reported a simple green strategy to fabricate T-C-SPION using green tea extract and citric acid. Also, the anti-cancer drug, DOX, was used as a model drug to fabricate DOX-loaded nanoparticles. Results:: The formed T-C-SPION nanoparticles were spherical with a diameter of 23.8 ± 0.8 nm, confirmed by Transmission Electron Microscopy (TEM). Besides, Dynamic Light Scattering (DLS) revealed that the prepared nanoparticles were water-dispersible and stable while stored in water for 6 weeks. The CCK-8 assay showed that T-C-SPION had a good cytocompatibility using different iron concentrations (10 ~ 120 ug/mL). Furthermore, T-C-SPION had a higher DOX encapsulation efficiency (Eencaps), around 43.2 ± 1.8 %, which resulted in a lagged release profile of DOX, compared to other types of iron oxide nanoparticles using green tea or citric acid alone. Next, cell viability assay indicated that T-C-SPION with a higher Eencaps showed superior and sustained cytotoxicity compared to the control group. Conclusion:: The developed iron oxide nanoparticles synthesized by green tea extract and citric acid in this paper could be considered as a potential drug carrier for cancer therapy applications.

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