<sup>1</sup>H‐NMR Spectroscopy as a New Tool in the Assessment of the Oxidative State in Edible Oils

Skiera, Christina; Steliopoulos, Panagiotis; Kuballa, Thomas; Holzgrabe, Ulrike; Diehl, Bernd

doi:10.1007/s11746-012-2051-9

Cited by 58 publications

(56 citation statements)

References 33 publications

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“…From the slope of the regression line and standard deviations of the EN, determined by the two methods ( σ GC and σ GPC1 ), the relative sensitivity (RS) of the two methods was calculated according to Skiera et al ():

{RS}_{GPC 1 / GC} = 0.944 \frac{σ_{GC}}{σ_{GPC 1}} = 3.5

…”

Section: Resultsmentioning

confidence: 99%

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Bantchev

Cermak

Durham

et al. 2019

J Americ Oil Chem Soc

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Using the universal calibration and the Mark‐Houwink equation (MHE) (ηj=KMjα), three batches of oleic estolide acids and their corresponding 2‐ethylhexyl esters were characterized using gel permeation chromatography (GPC). The MHE parameters in tetrahydrofuran (THF) at 40 °C were determined (for acids: α = 0.442 ± 0.003 and log10K=2.505 ± 0.007, for esters: α =0.531 ± 0.006 and log10K =2.794 ± 0.018). The fits of the GPC chromatograms yielded also the oligomeric composition of the estolides, which can be used to calculate the estolide number (EN) of an estolide mixture, and other molecular‐weight distribution parameters, such as number‐average molecular weight (Mn), weight‐average molecular weight (Mw), and dispersity (Ð). Using the Deming line fit, we concluded that the GPC should be expected to be approximately three times more sensitive than the currently used methods for determination of EN values.

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{RS}_{GPC 1 / GC} = 0.944 \frac{σ_{GC}}{σ_{GPC 1}} = 3.5

…”

Section: Resultsmentioning

confidence: 99%

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Bantchev

Cermak

Durham

et al. 2019

J Americ Oil Chem Soc

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“…1 H-and 13 C-NMR spectra of the oil samples (20 mL) were recorded on a Bruker Avance III, 400 MHz (Bruker, Inc., Bremen, Germany) NMR spectrometer in CDCl 3 as aprotic solvent at ambient temperature with TMS (tetramethylsilane) as an internal standard (in d ppm) [21]. The number of attached protons for the 13 C-NMR signals was determined from distortionless enhancement by polarization transfer (DEPT 135 ) experiments.…”

Section: Spectroscopic Analysismentioning

confidence: 99%

Concentration of C_20‐22n‐3 polyunsaturated fatty acids from Sardinella longiceps and fatty acid stabilization

Chakraborty

Joseph

2015

Euro J Lipid Sci & Tech

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Long chain n-3 polyunsaturated fatty acids from the refined oil from Sardinella longiceps were concentrated by low-temperature crystallization and urea complexation. Low-temperature crystallization (4°C) using acetone:ethylacetate (7:3, v/v) and urea complexation with urea-to-fatty acid ratio of 4:1 (w/w) afforded fatty acid concentrate (FAC) with greater than 60% C 20-22 n-3 fatty acids, and significant increase in NMR olefinic proton integral (at d 5.2-5.6). Ethylacetate fractions of seaweeds, Kappaphycus alvarezii, Hypnea musciformis, and Jania rubens, which possessed greater antioxidant activities, were added to FAC individually, and in nine factorial combinations (0.5%, w/w). The oxidative stabilities of these treatments were compared with FAC added with BHT and a-tocopherol in an accelerated storage study. A synergistic effect of ethylacetate fractions from K. alvarezii, H. musciformis, and J. rubens used at 0.1:0.2:0.2 (%, w/w) in preventing the oxidative degradation of FAC was observed. No traces of aromatics (d 6-7) and aldehydes (d 9-10) were present in the 1 H-NMR spectra of FAC added with seaweed extracts after the accelerated storage study, demonstrating that the seaweed extracts were able to prevent the formation of low molecular weight secondary oxidation products in the unsaturated system during storage.Practical applications: The present study demonstrated the process of concentrating the refined oil of S. longiceps using a step-wise process of low-temperature crystallization and urea complexation, which is significant to obtain greater than 60% C 20-22 n-3 fatty acids. The fatty acid concentrate has greater susceptibility towards oxidative rancidity resulting in the formation of toxic end products, and therefore, the prevention of oxidative deterioration of n-3 fatty acid concentrates is a major challenge for the fish oil industry. Effectiveness of seaweed derived antioxidatives as natural alternatives to synthetic antioxidants to prevent the formation of oxidation products in the concentrated fatty acids from fish oil has been established. The utility of nuclear magnetic resonance analyses as an effective tool for analyzing the chemistry and stability of concentrated n-3 polyunsaturated fatty acids has been demonstrated. This study is significant to produce stabilized fatty acid concentrate from marine fish oil for use in the food and pharmaceutical industries.

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“…[ 19 ] Presented by Skiera et al., titration results are significantly influenced by the matrix, the composition, and concentration of secondary phytochemicals leading to false positive or false negative peroxide value (PV) results. [ 20,21 ] Especially olive oil, which has a high commercial value, is subject to strict food quality control, which is regulated in the European Union by the Commission Regulation No. 2568/91.…”

Section: Introductionmentioning

confidence: 99%

“…; here hydroperoxides ( δ = 10.5–11.5 ppm) were quantified directly. [ 20 ] The primary limitation of this NMR method is the low sensitivity. Because various triacylglycerides lead to different hydroperoxides, the signal‐to‐noise ratio (S/N) of each individual hydroperoxide signal is low, and thus, the uncertainty of low‐oxidized oils with PV < 10 meq/kg can increase to ≥10% of S/N of 30).…”

Section: Introductionmentioning

confidence: 99%

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NMR Spectroscopy: Determination of Peroxide Value in Vegetable and Krill Oil by Using Triphenylphosphine as Tagging Reagent

Hafer

Holzgrabe

Wiedemann³

et al. 2020

Euro J Lipid Sci & Tech

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Hydroperoxides are formed as the primary product during lipid oxidation, being analyzed as the peroxide value to detect the degradation level of oils and fats. As an alternative to the classical titration method according to Wheeler, a 1 H-{ 31 P} decoupled NMR method is developed using triphenylphosphine (TPP) as a tagging agent. TPP reacts with peroxides to form TPP oxides. The quantification of the peroxide value is performed by comparing the amount of reacted TPP oxide and non-reacted TPP. This approach eliminates the requirement for an additional internal standard. Low-oxidized oils (peroxide value < 3 meq/kg) and high-oxidized oils with peroxide values of 150 meq/kg are precisely quantified with an relative standard deviation (RSD) of 4.90% and 0.16%, respectively. A total number of 108 oil samples are examined using the newly-developed 1 H-{ 31 P} decoupled NMR method, indicating the applicability for vegetable oils and krill oils. Practical Applications: The developed NMR method is applicable for the determination of the peroxide value in vegetable, marine and krill oils presenting a powerful alternative for the Wheeler titration method.

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¹H‐NMR Spectroscopy as a New Tool in the Assessment of the Oxidative State in Edible Oils

Cited by 58 publications

References 33 publications

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Concentration of C_20‐22n‐3 polyunsaturated fatty acids from Sardinella longiceps and fatty acid stabilization

NMR Spectroscopy: Determination of Peroxide Value in Vegetable and Krill Oil by Using Triphenylphosphine as Tagging Reagent

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1H‐NMR Spectroscopy as a New Tool in the Assessment of the Oxidative State in Edible Oils

Cited by 58 publications

References 33 publications

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Estolide Molecular Weight Distribution via Gel Permeation Chromatography

Concentration of C20‐22n‐3 polyunsaturated fatty acids from Sardinella longiceps and fatty acid stabilization

NMR Spectroscopy: Determination of Peroxide Value in Vegetable and Krill Oil by Using Triphenylphosphine as Tagging Reagent

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Product

Resources

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¹H‐NMR Spectroscopy as a New Tool in the Assessment of the Oxidative State in Edible Oils

Concentration of C_20‐22n‐3 polyunsaturated fatty acids from Sardinella longiceps and fatty acid stabilization