scholarly journals Oxidative stability of UV irradiated and X-rayed soybean oil incorporated with rose oil

2019 ◽  
Vol 70 (1) ◽  
pp. 286 ◽  
Author(s):  
M. T. Golmakani ◽  
S. Barani ◽  
N. Alavi ◽  
Z. Tahsiri
Keyword(s):  
Antioxidant Activity ◽  
Soybean Oil ◽  
Oxidative Stability ◽  
Uv Radiation ◽  
Oxidation Process ◽  
Energy Content ◽  
Oxidation Products ◽  
X Ray ◽  
Accelerated Storage ◽  
Rose Oil

The effects of UV radiation and X-ray on the oxidative stability of soybean oil were investigated. Also, rose oil was incorporated into soybean oil and its antioxidant activity was compared with that of α-tocopherol during accelerated storage. Treating the samples with radiation (UV and X-ray) stimulated the oxidation process in soybean oil in comparison with samples that did not receive radiation. X-rayed samples had significantly higher amounts of oxidation products than UV irradiated samples. The X-ray caused more oxidation in the samples due to its higher energy content. Also, the antioxidant activity of rose oil was comparable with that of α-tocopherol.

Antioxidant Activity of Phenolic Compounds in Ethanolic Extract of Hibiscus sabdariffa L. on Oxidative Stability of Soybean Oil

2021 ◽  
Vol 17 ◽  
Author(s):  
Patricia Joho Hiromoto ◽  
Wellington Mamoro Umeda ◽  
Neuza Jorge
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Soybean Oil ◽  
Lipid Oxidation ◽  
Oxidative Stability ◽  
Secondary Compounds ◽  
Total Phenolic ◽  
Hibiscus Sabdariffa ◽  
Total Phenolic Compounds ◽  
Accelerated Storage

Background: The current interest in natural antioxidants from vegetable sources has been increasing in Brazil, mainly in bioactive antioxidants. The Hibiscus sabdariffa L. is rich in bioactive compounds, besides having antioxidant and antimicrobial properties. Objective: To evaluate the antioxidant effect of hibiscus extract on the oxidative stability of soybean oil in accelerated storage test. Methods: The ethanolic extracts of calyces and hibiscus seeds were evaluated for total phenolic compounds and antioxidant activity using DPPH, FRAP and β-carotene/linoleic acid. The treatments: OS, Tocopherol, Extract and Mixture, were prepared and submitted to accelerated storage at 60°C. The samples were analyzed on days 0, 6 and 12 for peroxides index, p-anisidine, total oxidation value, oxidative stability and tocopherols. Results: The extract of calyces of hibiscus presented higher amounts of total phenolic compounds and antioxidant activity, therefore, it was added to soybean oil. The Extract treatment promoted greater efficiency to inhibit of the formation of primary and secondary compounds of lipid oxidation, and provided high oxidative stability to the soybean oil, in addition to greater retention of tocopherols, mainly α- and γ-tocopherol isomers. Conclusion: Among the treatments studied, Extract promoted greater efficiency in the inhibition of the formation of primary and secondary compounds of lipid oxidation, besides providing greater oxidative stability and greater retention of tocopherols during storage.

scholarly journals Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 944
Author(s):  
Arantzazu Valdés García ◽  
Ana Beltrán Sanahuja ◽  
Ioannis K. Karabagias ◽  
Anastasia Badeka ◽  
Michael G. Kontominas ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Storage Conditions ◽  
Oxidation Products ◽  
Oleic Acid Content ◽  
Sunflower Seeds ◽  
Secondary Products ◽  
Frying Process ◽  
Seed Moisture ◽  
Accelerated Storage ◽  
Roasting Process

The effect of different cooking processes such as frying and roasting on the oxidative stability of sunflower seeds was evaluated under accelerated oxidation and normal storage conditions. The fatty acid composition by GC-MS showed a higher amount of linoleic acid in fried samples due to the replacement of the seed moisture by the frying oil. On the other hand, roasted samples presented a higher oleic acid content. DSC and TGA results showed some decrease in the thermal stability of sunflower seed samples, whereas PV and AV showed the formation of primary and secondary products, with increasing oxidation time. Roasted sunflower seeds showed seven main volatile compounds characteristic of the roasting process by HS-SPME-GC-MS: 2-pentylfuran, 2,3-dimethyl-pyrazine, methyl-pyrazine, 2-octanone, 2-ethyl-6-methylpyrazine, trimethyl-pyrazine, and trans,cis-2,4-decadienal, whereas fried samples showed six volatile characteristic compounds of the frying process: butanal, 2-methyl-butanal, 3-methyl-butanal, heptanal, 1-hexanol, and trans,trans-2,4-decadienal. The generation of hydroperoxides, their degradation, and the formation of secondary oxidation products were also investigated by ATR-FTIR analysis. The proposed methodologies in this work could be suitable for monitoring the quality and shelf-life of commercial processed sunflower seeds with storage time.

Phase composition of autoclave oxidation products and its effect on gold coating

2021 ◽  
pp. 44-50
Author(s):  
S. I. Lyakh ◽  
S. S. Bakhvalov
Keyword(s):  
Precious Metal ◽  
Oxidation Process ◽  
Additional Treatment ◽  
Oxidation Products ◽  
X Ray Diffraction ◽  
Gold Coating ◽  
X Ray ◽  
Autoclave Oxidation ◽  
Pilot Tests ◽  
Gold Bearing

This paper describes the mineralogical studies of the solid products of autoclave oxidation. These products were obtained during autoclave pilot tests at a temperature of 225 oС and total pressure 3.25 МPa. Autoclave tests were carried out on the samples of sulfide gold-bearing concentrate of the Malomyr deposit. Mineralogical studies were provided using Mossbauer spectrometry, scanning electron microscope, X-ray fluorescence and X-ray diffraction analysis. It was found that the solid autoclave residues consist of basic ferric arsenate sulfate (Fe(AsO4)x(SO4)y(OH)z·wH2O), sodium jarosite (KFe3(SO4)2(OH)6), basic ferric sulfate (Fe(OH)SO4) and gangue minerals (muscovite, quartz, feldspars and others). The main relationships of the phase transformations in the autoclave oxidation process were described. Data obtained during these studies shows that some part of the gold may be associated with a secondary arsenic-containing phase formed in the autoclave oxidation process. This gold may be isolated from cyanidation solution and remain in the tailings. It was considered to subject the autoclave slurry to an additional treatment — Hot Cure process. This can minimize the loss of the precious metal during autoclave aftertreatment. As a result, a part of the secondary soluble phases (up to 10–50%) decomposes and dissolves. After that gold becomes accessible to the cyanide solution during sorption cyanidation. The increase in precious metal recovery is 2–5% for various samples.

Nano Aluminum Powders Oxidation in CO2 and O2 Environments

2013 ◽  
Vol 771 ◽  
pp. 113-117 ◽  
Author(s):  
Hong Bo Pei ◽  
Yang Liu ◽  
Hui Ren
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Oxidation Process ◽  
Oxidation Products ◽  
X Ray Diffraction ◽  
Aluminum Particles ◽  
Aluminum Powders ◽  
X Ray ◽  
Oxidation Processes ◽  
Oxidation Properties

An experimental study of oxidation of nano aluminum (Al) powders in CO2 and O2 is described. The oxidation is studied using thermogravimetric (TG) measurements from room temperature to 1500°C. Partially oxidized samples are recovered and their compositions are analyzed using X-ray diffraction. The oxidation product morphology was examined using SEM. Dimensional properties of aluminum particles have a significant influence on the oxidation processes. The nano aluminum reaction onset temperature was much lower than micro aluminum. Distinctly different oxidation properties of nano aluminum powders were shown between CO2 and O2. nano aluminum powders could ignite in O2 at fairly low temperatures around 530 °C. However ignition for nano aluminum powders in CO2 didn't appeared below 1500 °C. There was a weight loss in the TG curves at around 1200 °C for nano Al-CO2 system. It was thought that small amount of carbon formed in the oxidation process. The XRD showed that both the nano aluminum oxidation products were α-Al2O3 in CO2 and O2.

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