The effect of olive leaves and their harvest time on radical scavenging activity and oxidative stability of refined olive oil

2014 ◽  
Vol 6 (2) ◽  
pp. 141-149 ◽  
Author(s):  
T.M. Keceli ◽  
F. Harp
Antioxidants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 996
Author(s):  
Vito Michele Paradiso ◽  
Federica Flamminii ◽  
Paola Pittia ◽  
Francesco Caponio ◽  
Carla Di Mattia

Omics approaches are recently being applied also in food lipid oxidation, to increase knowledge of oxidation and antioxidation mechanisms. The so-called oxidomics throws a wider spot of light on the complex patterns of reactions taking place in food lipids, especially in dispersed systems. This research aimed to investigate the radical scavenging activity of olive oil phenolic antioxidants (OPAs) in O/W emulsions, as affected by the phase in which they were added. This allowed one to assess whether different behaviors could be expected from antioxidants originally present in phenolic-rich olive oils compared to natural antioxidants added in the water phase during emulsion production. Hydroperoxide decomposition kinetics and the analysis of volatile pattern provided an outline of antioxidation mechanisms. Though being effective in slowing down oxidation when added both in the oil and water phase, OPAs interfered in different ways with oxidation pathways, based on the phase in which they were added. OPAs added to the water phase were more effective in slowing down hydroperoxide decomposition due to the hydrophilic radical initiator. On the other hand, OPAs present in the oil were more effective in preventing radical propagation, with relevant consequences on the volatile pattern.


Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 373
Author(s):  
Jana Goritschnig ◽  
Klaudia Tadus ◽  
Jürgen König ◽  
Marc Pignitter

Non-enzymatic browning reactions between lipid aldehydes and aminophospholipids might play an important role in the oxidative stability of cold-pressed vegetable oils. We, therefore, aimed to study the Maillard-type reaction between hexanal, a lipid oxidation product of linoleic acid, and phosphatidylethanolamine (PE (16:0/18:1)) at a ratio of 2:1 at conditions representative of the extraction of cold-pressed soybean oils (CPSBO) and determine the radical scavenging activity of the carbonyl-amine adducts with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The reaction product, 2-pentyl-3,5-dibutyl-dihydropyridine, could be identified by means of LC-ESI-QTOF-MS/MS. The formation of this nitrogen-containing heterocycle significantly increased with time and temperature (p < 0.05). The products formed during the carbonyl-amine reaction between PE (16:0/18:1) and hexanal at 60 °C showed a radical scavenging activity of approximately 20% (p < 0.05). The fraction, containing 2-pentyl-3,5-dibutyl-dihydropyridine, contributed to, but was not solely responsible for, the radical scavenging activity (p < 0.05). Incubation of CPSBO fortified with PE (16:0/18:1) at 60 °C for 60 min had the strongest radical scavenging activity of 85.1 ± 0.62%. Besides 2-pentyl-3,5-dibutyl-dihydropyridine, other carbonyl-amine adducts might impact the radical scavenging activity of CPSBO as well. The oxidative stability of CPSBO might be increased by promoting the formation of carbonyl-amine reaction products, such as 2-pentyl-3,5-dibutyl-dihydropyridine.


2013 ◽  
Vol 781-784 ◽  
pp. 1776-1779
Author(s):  
Li Qin Jiang

The aim of this study was to investigate the effect of antioxidants of soybean oil and virgin olive oil during heating. Tocopherol and total phenol content in oils were determined by HPLC and Folin test, respectively. Antioxidant activity was measured with scavenging-activity (RSA) of free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH·) by spectrophotometer. Among the antioxidants studied, comparable activity was found between Trolox and tocopherol, while activity of phenol was low in the study. Tocopherol compounds contribute the RSA of soybean oil, and the RSA of virgin olive oil was from phenol compound as well as tocopherols. Our study showed the variety and content of antioxidants influence RSA of vegetable oils, which concerned the stability and nutrition quality of vegetable oil.


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