Different studies have shown that detection of free radicals by ESR spin trapping provides useful information on the susceptibility to oxidation of bulk oils and accordingly on the oxidative stability of different samples for comparative purposes. With the same goal, ESR spin trapping was evaluated in this work for in situ detection of radicals in dried microencapsulated oils (DMOs). By testing different oils, encapsulation matrices and oxidation conditions, results showed that ESR spin trapping can be useful to evaluate the oxidative susceptibility of DMOs, but ESR data should be interpreted cautiously, as the great complexity of the reactions involved may lead to data misinterpretations. Conditions for oxygen availability can have important impacts on the rates of both spin trapping and spin-adduct quenching affecting the levels of radicals observed. The kinetics of oxidation, spin trapping and spin-adduct decay should be known first in bulk oils for correct data interpretation in DMOs.
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http://dx.doi.org/10.1016/j.foodchem.2020.128227 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
A small but growing set of radical SAM (-adenosyl-l-methionine) enzymes catalyze the radical mediated dehydration or dehydrogenation of 1,2-diol substrates. In some cases, these activities can be interchanged via minor structural perturbations to the reacting components raising questions regarding the relative importance of hyperconjugation, proton circulation and leaving group stability in determining the reaction outcome. The present work describes trapping and electron paramagnetic resonance (EPR) characterization of an α-hydroxyalkyl radical intermediate during dehydration and dehydrogenation of cytosylglucuronic acid and its derivatives catalyzed by the radical SAM enzyme BlsE and its Glu189Ala mutant from the blasticidin S biosynthetic pathway.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China.
The most well-known hydroxyl radical (OH)-generating system is the classic iron-mediated Fenton reaction. Thiourea has been considered as an efficient OH scavenger and is frequently used to study the role of OH in various biochemical and medical research studies. Here we found that the highly reactive OH can be produced from thiourea and HO through a metal-independent pathway, as measured by electron spin resonance (ESR) secondary radical spin-trapping and fluorescent methods.
View Article and Find Full Text PDFSci Rep
January 2025
Centre for Molecular and Materials Science, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada.
This paper describes muon spin spectroscopy studies of 12-phosphatetraphene stabilized by a peri-trifluoromethyl group and a meso-aryl substituent. Even though the prepared solution in tetrahydrofuran (THF) was quite dilute (0.060 M) for transverse-field muon spin rotation (TF-µSR) measurements, the π-extended heavier congener of tetraphene presented a pair of signals due to a muoniated radical from which the muon hyperfine coupling constant (hfc) was determined.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
Chirality-induced spin selectivity (CISS) generates giant spin polarization in transport through chiral molecules, paving the way for novel spintronic devices and enantiomer separation. Unlike conventional transport, CISS magnetoresistance (MR) violates Onsager's reciprocal relation, exhibiting significant resistance changes when reversing electrode magnetization at zero bias. However, its underlying mechanism remains unresolved.
View Article and Find Full Text PDFNanoscale
January 2025
School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, South Korea.
Eliminating hazardous antibiotics from aquatic environments has become a major concern in recent years. Tetracycline (TC) compounds pose a challenge for the selective degradation of harmful chemical groups. In this study, we successfully designed carbon vacancies in a gCN@WC (GW) heterostructure for the effective removal of TC pollutants under visible light.
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