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Ishida, N.; Ogawa, H.; Koizumi, M.; Kano, H.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S22::AID-OMR206>3.0.CO;2-5pmid: N/A
Ontogenetic changes of water status and accumulated soluble compounds in growing cherry fruits were examined by 1H NMR imaging, 1H NMR localized spectral imaging and 13C NMR spectroscopy. Water status was contradictory between the seed and pericarp of the fruit in relation to growth stages. There was a large amount of high‐mobility water present in the seed, whereas only a small amount was present in the pericarp during the early growth stages. The diffusion coefficient of seed water was determined as 2.1×10‐5 cm2 s‐1 at the maximum, which corresponded to that of pure water (2.14×10‐5 cm2 s‐1 at 25±1°C). Water in the seed decreased in amount and mobility whereas that in the pericarp increased with maturation. The diffusion coefficient of pericarp water increased from 1.0×10‐5 to 1.6×10‐5 cm2 s‐1 as the fruit ripened. Sugars accumulated in the pericarp with increasing water content, but disappeared with further ripening of the fruit. This suggests that over‐maturation results in loss of sweetness and firmness. NMR imaging could probe changes in the physiological condition of the fruit with growth stages. © 1997 John Wiley & Sons, Ltd.
Sacchi, Raffaele; Addeo, Francesco; Paolillo, Livio
doi: 10.1002/(SICI)1097-458X(199712)35:13<S133::AID-OMR213>3.0.CO;2-Kpmid: N/A
The authentication and quality assessment of virgin olive oil were performed using high‐resolution 1H and 13C NMR spectroscopy. An overview of the various determinations currently assessed is presented with emphasis on the detection of adulteration with foreign (seed) oils and esterified or refined olive and olive‐pomace oils. Recent results on the NMR analysis of natural compounds (diacylglycerols, free fatty acids, aldehydes, polyphenols, etc.) related to the quality‐freshness of virgin olive oil are also reported. The possible contribution of high‐resolution NMR to the authentication of geographical origin of virgin olive oil is discussed. © 1997 John Wiley & Sons, Ltd.
Gambhir, P. N.; Pande, P. C.; Ratcliffe, R. G.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S125::AID-OMR225>3.0.CO;2-8pmid: N/A
In vivo 31P NMR spectra of wheat, soybean and mustard seeds were recorded during ripening. Signals were detected from phosphomonoesters, cytoplasmic and vacuolar inorganic phosphate (Pi), phytate, nucleoside triphosphate (NTP) and nucleoside diphosphosugars. The spectra of extracts showed an accumulation of phytate during development, accompanied by a decrease in inorganic phosphate, and this was reflected in the in vivo spectra. The intrinsic width of the resonances was a significant obstacle to the interpretation of the in vivo spectra in all three cases, and the problem became more severe with increasing maturity. However, it was still possible to use the chemical shift of the cytoplasmic Pi signal to monitor cytoplasmic pH in both soybean and mustard, and the results provide evidence for the existence of a hypoxic state in developing seeds during the active biosynthetic phase. © 1997 John Wiley & Sons, Ltd.
Rutledge, D. N.; Barros, A. S.; Gaudard, F.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S13::AID-OMR199>3.0.CO;2-Ppmid: N/A
Time domain (or low resolution pulse) NMR can generate a range of relaxation curves (CPMG, I–R, P–S, HSE, FID, etc.) which may vary depending on the characteristic of the product being controlled—water content, hydration state, solid fat content, iodine number or even authenticity of origin. Very often, the NMR signal is decomposed into a sum of exponential relaxation curves and the calculated NMR parameters (e.g. R1, R2, M0) are correlated with the property under study. Chemometric techniques, such as analysis of variance (ANOVA) and factor analysis, were shown to be effective means of determining whether a given set of NMR signals contains any interesting information before proceeding to use fastidious and often uncertain signal decomposition procedures. These techniques were applied to NMR signals acquired for spreads and gelatines with different compositions, to mixtures of a cation (Cu2+) and a ligand (tetraphenylporphin) and to glycine solutions at different pH values. © 1997 John Wiley & Sons, Ltd.
Mazzoni, Vanina; Bradesi, Pascale; Tomi, Félix; Casanova, Joseph
doi: 10.1002/(SICI)1097-458X(199712)35:13<S81::AID-OMR202>3.0.CO;2-Epmid: N/A
A method is described which allows the identification of individual carbohydrates of multi‐component artificial mixtures using the computer‐aided analysis of their 13C NMR spectra, without previous separation. Quantitation of mono‐, di‐ and trisaccharides was carried out after improvement of the experimental procedure and using an internal standard. The procedure was then applied to authentic honeys of different floral types, harvested in Corsica (France). Several oligosaccharides (identification of some of these is not easy by chromatographic techniques) were observed at levels ranging from 0.4 to 3.3%. In addition, the fructose/glucose ratio, which has an influence on crystallization, was easily obtainable. © 1997 John Wiley & Sons, Ltd.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S146::AID-OMR196>3.0.CO;2-Xpmid: N/A
The different characteristics between frequency domain and time domain analysis techniques are detailed for their application to in vivo MRS data sets. With the aim of quantitative analysis of MRS signals, i.e. estimation of parameters in the physical model function that describes the MRS experiment, it is considered desirable to avoid any preprocessing of the data, resulting in a preference for time domain parameter estimation techniques. A historical overview is provided for the time domain analysis methods presented in the literature, and a number of time domain methods are described in detail. Finally, the MRUI software package, providing an interactive graphical user interface for a variety of time domain methods, is summarized. © 1997 John Wiley & Sons, Ltd.
Constantinesco, A.; Choquet, P.; Cauffet, G.; Fournier, J. M.; Ravier, S.; Drillon, J. M.; Aubert, G.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S69::AID-OMR198>3.0.CO;2-5pmid: N/A
Dedicated low‐field (0.1 T) resistive magnets equipped with solenoid coils were devised for high‐resolution and rapid magnetic resonance imaging (MRI) in agricultural and food science. The maximum pixel resolution is 0.1×0.1 mm with a 0.8 mm slice thickness, and 3D T1, T2 and T2* weighted images are obtained in 3 s–6 min depending on the contrast and number of slices. In place of resistive magnets two desktop permanent magnet designs are also described and their field characteristics and possible usefulness for small‐sized low‐cost MRI scanners, are discussed. © 1997 John Wiley & Sons, Ltd.
doi: 10.1002/(SICI)1097-458X(199712)35:13<S61::AID-OMR214>3.0.CO;2-9pmid: N/A
Pulsed 1H NMR in vivo difference spectroscopy and germination were combined to elucidate the effect of exogenously applied estriol or ethanol on water retention in fully hydrated rape seeds. The presence of estriol or ethanol in the imbibition medium resulted in a reduction of the photoreversible phytochrome. An approach to the assessment of cell membrane permeability related to the intracellular water exchange rate, using the bi‐exponential feature in the water proton spin–lattice relaxation rate R1 and spin–spin relaxation rate R2, is presented. The intracellular water exchange rate increases approximately two‐ and three‐fold in seeds pre‐treated with estriol or ethanol solution in comparison with water imbibed seeds. The activation energy for the germination rate was 61±6, 42±4 and 37±4 kJ mol‐1 and the transition temperature was 281±2, 286±2 and 284±2 K for seeds imbibed with water, estriol and ethanol solution, respectively. The temperature dependence of the intracellular water exchange rate showed comparable values of activation energy and transition temperatures. All the results support the hypothesis that the two effects, thermal activation and increase in the seed cell membrane permeability, combine during water transport into the cell and result in the germination of rape seeds imbibed with estriol or ethanol solution. © 1997 John Wiley & Sons, Ltd.
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