Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment

Various studies have demonstrated that employing ESR spin trapping to detect free radicals yields valuable insights into the vulnerability of bulk oils to oxidation. Consequently, this method can be employed to assess and compare the oxidative stability of different samples. This study was conducted...

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Main Authors: Lu Huimin, Li Yongfu, Qiu Ju
Format: Article
Language:English
Published: Elsevier 2024-03-01
Series:Heliyon
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2405844024031992
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author Lu Huimin
Li Yongfu
Qiu Ju
author_facet Lu Huimin
Li Yongfu
Qiu Ju
author_sort Lu Huimin
collection DOAJ
description Various studies have demonstrated that employing ESR spin trapping to detect free radicals yields valuable insights into the vulnerability of bulk oils to oxidation. Consequently, this method can be employed to assess and compare the oxidative stability of different samples. This study was conducted to investigate the production and transformation of free radicals and trans isomers in linseed oil when subjected to different temperatures and durations of heating. These analyses revealed that the peak levels of free radicals PBN adducts were evident in linseed oil heated to 120 °C, while these levels decreased within 90 min and were absent at a higher temperature of 180 °C. Free radical PBN adducts were readily degraded at 180 °C. Levels of heat-induced trans isomers rose in linseed oil samples with rising temperatures but began to degrade at temperatures exceeding 240 °C partially. The content examination of these trans isomers revealed that the double bonds located at positions 9 and 15 exhibited a higher susceptibility to isomerization compared to the double bond at position 12. Furthermore, the values of k and Ea indicated that the synthesis of tri-trans-α-linolenic acid (TALAs) was more challenging compared to double-TALAs, and double-TALAs were more challenging than single-TALAs. This was because the tri-TALAs has a higher Ea value than the mono-TALAs and double-TALAs. The study has demonstrated that subjecting linseed oil to high-temperature heating leads to the production of free radicals and trans isomers. And PBN radical adduct is unstable at 180 °C and the double bonds at positions 9 and 15 could be isomerized more easily than that at position 12. These results indicated that controlling the formation of free radicals and single-TALAs isomers may be the key way to reduce the trans isomers of linolenic acid during cooking oil heating. In the follow-up study, we found that VE, VK3, ethyl caffeic acid and resveratrol had significant inhibitory effects on the formation of TALAs of linolenic acid, and the highest inhibitory rate of resveratrol with 5% addition could be reached to 30.86%. The above substances can be applied to the thermal processing of linseed oil to prevent the formation of TALAs.
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spelling doaj.art-4eb9a06c2684411abe0bc04cc7c741982024-04-04T05:04:25ZengElsevierHeliyon2405-84402024-03-01106e27168Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatmentLu Huimin0Li Yongfu1Qiu Ju2Institute of Integrated Agricultural Development (Guizhou Academy of Agricultural Sciences), Guiyang, China; College of Food Science and Engineering (Guiyang College), Guiyang, ChinaInstitute of Integrated Agricultural Development (Guizhou Academy of Agricultural Sciences), Guiyang, China; College of Food Science and Engineering (Guiyang College), Guiyang, China; Corresponding author. Institute of Integrated Agricultural Development, Guizhou Academy of Agricultural Sciences, Guiyang, China.Institute of Integrated Agricultural Development (Guizhou Academy of Agricultural Sciences), Guiyang, China; College of Food Science and Engineering (Guiyang College), Guiyang, ChinaVarious studies have demonstrated that employing ESR spin trapping to detect free radicals yields valuable insights into the vulnerability of bulk oils to oxidation. Consequently, this method can be employed to assess and compare the oxidative stability of different samples. This study was conducted to investigate the production and transformation of free radicals and trans isomers in linseed oil when subjected to different temperatures and durations of heating. These analyses revealed that the peak levels of free radicals PBN adducts were evident in linseed oil heated to 120 °C, while these levels decreased within 90 min and were absent at a higher temperature of 180 °C. Free radical PBN adducts were readily degraded at 180 °C. Levels of heat-induced trans isomers rose in linseed oil samples with rising temperatures but began to degrade at temperatures exceeding 240 °C partially. The content examination of these trans isomers revealed that the double bonds located at positions 9 and 15 exhibited a higher susceptibility to isomerization compared to the double bond at position 12. Furthermore, the values of k and Ea indicated that the synthesis of tri-trans-α-linolenic acid (TALAs) was more challenging compared to double-TALAs, and double-TALAs were more challenging than single-TALAs. This was because the tri-TALAs has a higher Ea value than the mono-TALAs and double-TALAs. The study has demonstrated that subjecting linseed oil to high-temperature heating leads to the production of free radicals and trans isomers. And PBN radical adduct is unstable at 180 °C and the double bonds at positions 9 and 15 could be isomerized more easily than that at position 12. These results indicated that controlling the formation of free radicals and single-TALAs isomers may be the key way to reduce the trans isomers of linolenic acid during cooking oil heating. In the follow-up study, we found that VE, VK3, ethyl caffeic acid and resveratrol had significant inhibitory effects on the formation of TALAs of linolenic acid, and the highest inhibitory rate of resveratrol with 5% addition could be reached to 30.86%. The above substances can be applied to the thermal processing of linseed oil to prevent the formation of TALAs.http://www.sciencedirect.com/science/article/pii/S2405844024031992Linseed oilElectron spin resonanceFree radicalsTrans-fatty acidsGas chromatography
spellingShingle Lu Huimin
Li Yongfu
Qiu Ju
Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
Heliyon
Linseed oil
Electron spin resonance
Free radicals
Trans-fatty acids
Gas chromatography
title Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
title_full Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
title_fullStr Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
title_full_unstemmed Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
title_short Characterization of the evolution of free radicals and TALAs in linseed oil during heat treatment
title_sort characterization of the evolution of free radicals and talas in linseed oil during heat treatment
topic Linseed oil
Electron spin resonance
Free radicals
Trans-fatty acids
Gas chromatography
url http://www.sciencedirect.com/science/article/pii/S2405844024031992
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AT qiuju characterizationoftheevolutionoffreeradicalsandtalasinlinseedoilduringheattreatment