Determination of Dry Matter Content in Potato Tubers by Low-Field Nuclear Magnetic Resonance (LF-NMR)

Hansen, Christian Lyndgaard; Thybo, Anette Kistrup; Bertram, Hanne Christine; Viereck, Nanna; Berg, Frans van den; Engelsen, Søren Balling

doi:10.1021/jf101319q

Cited by 76 publications

(36 citation statements)

References 26 publications

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“…The distributed exponential approach utilizes a regularization method to the inverse Laplace transformation yielding a continuous distribution of T 2 relaxation times (Provencher 1982). Mathematically, the distributed exponential fitting is ill-defined because it is sensitive to the constraints employed (Hansen et al, 2010;Martens and Thybo, 2000). In addition, there is a shorter T 2 relaxation component observed in the range of 10-15 ms.…”

Section: Resultsmentioning

confidence: 99%

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

2017

Grasas y Aceites

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SUMMARY:Adulteration of olive oil using unhealthy substitutes is considered a threat for public health. Low-field (LF) proton (1H) nuclear magnetic resonance (NMR) relaxometry and ultra-violet (UV) visible spectroscopy are used to detect adulteration of olive oil. Three different olive oil with different oleoyl acyl contents were mixed with almond, castor, corn, and sesame oils with three volumetric ratios, respectively. In addition, Arbequina olive oil was mixed with canola, flax, grape seed, peanut, soybean, and sunflower seed oils with three volumetric ratios. Transverse magnetization relaxation time (T 2 ) curves were fitted with bi-exponential decaying functions. T 2 times of each mixture of olive oils and castor oils, and olive oils and corn oils changed systematically as a function of volumetric ratio. To detect the adulteration in the mixtures with almond and sesame oils, both LF 1 H NMR relaxometry and UV-Vis spectroscopy were needed, where UV-Vis-spectroscopy detected the adulteration qualitatively. In the mixtures of Arbequina olive oil and flax, peanut, soybean, and sunflower seed oils, both T 21 and T 22 values became longer systematically as the content of the olive oil was decreased. The unique UV-Vis maximum absorbance of flax oil at 320.0 nm shows the adulteration of olive oil qualitatively. KEYWORDS: Adulteration detection; Low-field NMR relaxometry; Olive oil; UV-Vis spectroscopyRESUMEN: Detección de la adulteración de aceite de oliva mediante relaxometría magnética nuclear de campo bajo y espectroscopía UV-Vis sobre mezcla de aceite de oliva con diversos aceites comestibles. La adulteración del aceite de oliva con sustituyentes menos saludables es una amenaza para la salud pública. En este trabajo, la detección de la adulteración del aceite de oliva se demuestra utilizando tanto relaxometría magnética nuclear de campo bajo (LF) de protones ( 1 H) (RMN) y espectroscopía visible y ultra-violeta (UV). Tres muestras de aceites de oliva con diferentes contenidos en oleico se mezclaron con aceites de almendra, ricino, maíz y sésamo con tres relaciones volumétricas. Además, el de arbequina de California se mezcló con cánola, lino, semilla de uva, cacahuete, soja y aceites de girasol con tres relaciones volumétricas. Las curvas de tiempo de relajación de magnetización transversal (T2) fueron completadas con funciones de decaimiento biexponencial. Los tiempos T2 determinados para cada mezcla de aceite de oliva con ricino y maíz cambian sistemáticamente conforme las relaciones volumétricas. Para detectar la adulteración de los aceites de oliva con aceites de almendra y de sés-amo, se necesitan tanto relaxometría LF 1H RMN como la espectroscopía UV-Vis. En las mezclas de aceite de oliva arbequina con aceites de lino, maní, soja y girasol, ambos valores T21 y T22 se hicieron mayores sistemáti-camente conforme el porcentaje de aceite de oliva se reduce en la mezcla. El máximo de absorbancia UV-Vis del aceite de lino a 320,0 nm demostrará la adulteración del aceite de oliva cualitativamente.

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Section: Resultsmentioning

confidence: 99%

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

2017

Grasas y Aceites

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“…To characterize these morphological structures, we suggested using 1 H Low Field (LF) NMR energy relaxation time analysis to generate multi‐dimensional graphics of the individual peaks representing PUFA's internal morphological and chemical aggregates, and to correlate it with the mechanism of PUFA oxidation and antioxidant efficacy. This technology is non‐destructive and does not require the use of solvents or sample preparation . Furthermore, we recently reported that 1 H LF‐NMR may evaluate both the primary and the secondary oxidation products in the same graph as separate peaks .…”

Section: Introductionmentioning

confidence: 99%

¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Resende

Linder

Wiesman

2019

Euro J Lipid Sci & Tech

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A major stability issue of food and other products containing lipids is their susceptibility to oxidation and the efficacy of endogenous or exogenous antioxidants that are sensitive to internal morphological and chemical structures which are difficult to characterize with current analytical methods. This work develops signal reconstruction of 1H LF‐NMR spin‐lattice (T1) and spin‐spin (T2) energy relaxation times into 2D T2 versus T1 peak graphs of the internal chemical and morphological arrangements within lipid materials, with the potential for efficient structural studies of lipid oxidation and antioxidant efficacy in complex foods. This novel NMR inverse Laplace transformation (ILT) signal processing reconstruction is now applied in a PUFA‐rich linseed oil's thermal autoxidation and antioxidant efficacy study. To characterize antioxidant efficacy, it is important to understand the mechanism of oxidation and the chemical and morphological structural aspects. The initial steps of oxidation show a clear peak shift to shorter T2 versus T1 peak values, for the different poly‐unsaturated fatty acids (PUFA), which for mono‐unsaturated and saturated FAs remain unchanged. These peak shifts are within an oxidation time period needed for hydroperoxides formation. For longer oxidation times a new set of T2 versus T1 peaks are generated with shorter T2 and stable and/or increased T1 values, suggesting formation of aldehydes and polymerized oxidation end products. The chemical changes of the fatty acids of linseed oil are confirmed by their gas chromatography analysis during the studied time interval. Similarly peroxides and aldehydes formation trends are confirmed by PV and p‐ansidine tests, respectively for the same time points. Based on the oxidation study the control of T1 and T2 relaxation times by α tocopherol antioxidant is characterized. In effect α tocopherol antioxidant maintains peak stability during linseed oil's thermal autoxidation, in a 2D T2 versus T1 relaxation time graph of peaks assigned to chemical morphological structures, demonstrating α tocopherol's ability to minimize linseed oil's oxidation. Practical Application: Monitoring of food products oxidation and quality control. 1H LF‐NMR T1 and T2 energy relaxation times reconstructed with PDCO into 2D spectra of material analysis has proven to be an advantageous tool to monitor complex chemical and morphological structural changes during the autoxidation of PUFA‐rich linseed oil. It is suggested that an initial oxidation phase generates a shift, of the original linseed peaks along the T1 = T2 diagonal due to hydroperoxide formation. At longer oxidation times there is an accumulation of peaks below the diagonal line assigned to oligomeric/polymeric termination products, generating a significant “bending effect.” α tocopherol addition at effective concentrations is able to change this pattern of PUFA‐rich linseed oil oxidation by blocking early peaks shift and late bending effect.

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“…Low-field NMR relaxometry remains a nondestructive alternative, which is commonly used to investigate water contents, mobility, and interactions in matrix systems, such as plant organs 14,15 and particularly in imbibing and germinating seeds. 8,16−24 Deconvolution of the multiexponential curves obtained from longitudinal (T 1 ) and transverse (T 2 ) relaxations allows identifying groups and proportions of water protons that share environments, interactions or molecular exchange rates.…”

Section: Seed Germination Represents An Important Means Of Plants'mentioning

confidence: 99%

Water Mobility and Microstructure Evolution in the Germinating Medicago truncatula Seed Studied by NMR Relaxometry. A Revisited Interpretation of Multicomponent Relaxation

Lahaye

Falourd

Limami

et al. 2015

J. Agric. Food Chem.

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The water status of Medicago truncatula Gaertn. seed was followed by low-field NMR relaxometry during germination with and without oryzalin or fusicoccin used as growth modulators. T1 and T2 relaxation times and proportions P1 and P2 were determined on fresh, frozen, and freeze-thawed samples to characterize changes in water dynamics and compartmentation and in the nonfreezing water fraction. The results demonstrate that low-field NMR relaxometry allowed differentiating germination phases and events occurring during them as well as perturbations related to the presence of growth modulators. The results provide clear evidence that the classical multicomponent relaxation interpretation cannot directly relate T2 components and morphological compartments in biological tissue.

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Determination of Dry Matter Content in Potato Tubers by Low-Field Nuclear Magnetic Resonance (LF-NMR)

Cited by 76 publications

References 26 publications

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Water Mobility and Microstructure Evolution in the Germinating Medicago truncatula Seed Studied by NMR Relaxometry. A Revisited Interpretation of Multicomponent Relaxation

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Determination of Dry Matter Content in Potato Tubers by Low-Field Nuclear Magnetic Resonance (LF-NMR)

Cited by 76 publications

References 26 publications

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

Detection of olive oil adulteration by low-field NMR relaxometry and UV-Vis spectroscopy upon mixing olive oil with various edible oils

1H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Water Mobility and Microstructure Evolution in the Germinating Medicago truncatula Seed Studied by NMR Relaxometry. A Revisited Interpretation of Multicomponent Relaxation

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Product

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¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants