• Journal of Environmental Impact Assessment
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• v.30 no.2
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• pp.132-139
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• 2021

Laboratory-scale experiments were conducted to assess the effect of oxidative decomposition of polycyclic aromatic hydrocarbons (PAHs) in field soil using peroxy-acid. The study soil texture is sandy soil containing 19.2 % of organic matter at pH 6.8. Among polycyclic aromatic hydrocarbons (PAHs) in the study soil, the concentration of benzo(a)pyrene is 2.23 mg/kg which is three times higherthan the Korea standard level. Therefore benzo(a)pyrene was selected as the target study PAH for the treatment by peroxy-acid oxidation using peroxy-acid coupled with hydrogen peroxide, and the efficiency of the oxidative decomposition of benzo(a)pyrene was assessed for the different organic acids and dosages of an organic acid and hydrogen peroxide. Propionic acid among the tested organic acids showed the highest efficiency of benzo(a)pyrene reduction in the peroxyacid oxidation treatment and finally satisfied the Korea standard level.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.909-913
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• 2001

The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.837-843
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• 1997

In oxidized polyethylene wax preparation, the effects of main parameters such as the property of used wax, oxidation time, oxidation temperature, air feed rates on the change of acid-numbers were investigated. The change in polymer property was also investigated. The results showed under given reaction conditions, the acid numbers with oxidation temperature increased upto $160^{\circ}C$, but at higher temperature, it decreased. The base resin which was lower molecular weight had higher acid number. The result showed molecular weight as a experimental parameter was more effective than density in oxidation experiment. In milder condition, free radical initiator was used for catalyst to get higher acid-numbers, which was successful in comparison to the non-catalyst system. Also the catalyst with longer half-life was efficient, in order of DCPO, HOPO and BPO.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.37-41
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• 1992

Starch solid system was used to investigate the effects of lipoxygenase, linoleic acid and water activity on the oxidation of ${\beta}-carotene$ or ${\alpha}-tocopherol$. ${\beta}-carotene$ or ${\alpha}-tocopherol$ was co-oxidized severely with linoleic acid by lipoxygenase, and these were reduced to 19% and 5% of initial concentration, respectively, after 2 days storage at $a_w$ 0.72 in the system. The concentration of ${\beta}-carotene$ and the destruction rates were linearly correlated. However, the ${\beta}-carotene$ was very stable in the system without linoleic acid and lipoxygenase. The oxidation products of ${\alpha}-tocopherol$ were considered as ${\alpha}-tocopheryl$ quinone and ${\alpha}-tocopheryl$ dimer, and the level of ${\alpha}-tocopherol$ quinone increased as the reaction time increased.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.183-187
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• 2008

Alkyl thiosulfi(o)nates, analogs of allyl-2-propene-1-thiosulfinate isolated from Allium sativum and having antibacterial activity, were chemically synthesized and their biological activities were investigated. Alkyl thiosulfinates were prepared by oxidation of corresponding disulfides with organic peroxy acid, while alkyl thiosulfonates could be obtained by oxidation of the alkyl thiosulfinates using sodium periodate. All synthetic thiosulfi(o)nates showed antibacterial activity against Staphylococcus aureus B33 and antifungal activity against Candida utilis ATCC42416. Further more synthetic alkyl thiosulfonates displayed antioxidant activity and have also prevention effect of platelet aggregation induced by collagen in rat.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.593-597
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• 2010

This study investigated the properties and antioxidative activities of phenolic acid concentrates of rice bran. Rice bran contains bioactive substances such as phenolic compounds, which can provide health benefits as natural antioxidants. This study examined how levels of phenolic acids can be obtained efficiently through various extraction methods. The extractions of defatted rice bran were followed by using ethylacetate (RBE-I), ethylacetate after alkaline hydrolysis (RBE-II), and 80% methanol (RBE-III). For all extracts, yields (%), total polyphenol contents (TPC), various phenolic acids and antioxidative activities were estimated. RBE-II had the highest total polyphenol contents (526.72 mg/100 g rice bran) and showed high antioxidative activity (74.7%). To concentrate the phenolic acids, RBE-II was passed through Sep-pak $C_{18}$ Vac cartridge and F1-RBE-II was collected by the elution of 50% methanol. The total phenolic content of F1-RBE-II (736.8 mg/100 g rice bran) was higher than that of RBE-II (367.1 mg/100 g rice bran), and the ratios of ferulic acid (73%) and sinapic acid (14%) increased. As RBE-II was analysed by HPLC, 6 different phenolic acids were found via chromatography, whereas F1-RBE-II showed 5 different peaks and the major phenolic acid was identified as ferulic acid. The ABTS radical scavenging activity of F1-RBE-II was the highest among the rice bran extracts. In a ${\beta}$-carotene-linoleic acid model system, linoleic acid oxidation was reduced by F1-RBE-II (73%) and RBE-II (35%).