Changes in Volatile Compounds during Ripening in Grapes of Airén,                Macabeo and Chardonnay White Varieties Grown in La Mancha Region (Spain)

Changes in volatile compounds in musts and skins of grapes of Airén, Macabeo and Chardonnay white varieties were determined during ripening. The musts of the Airén variety contained higher concentrations of c-3-hexenol; musts of the Macabeo variety were the richest in t-3-hexenol and 2,4-hexadienal, while the Chardonnay musts stood out for having higher concentrations of benzaldehyde, phenylacetaldehyde and benzyl alcohol. The skins of the three varieties were both qualitatively and quantitatively richer in volatiles than were the musts. The skins of the Airén grapes had the highest levels of nerol. Airén grapes were the only variety in which citronellol was present in the skins. Low concentrations of eugenol were detected in the skins of the Chardonnay grape variety but were not present in the other two varieties. Changes in the concentration of the volatile compounds during ripening were not uniform; this made difficult the determination of the optimum level of ripening for each variety on the basis of the volatile compound content. Nevertheless, results indicated that C6 compounds and terpene concentrations reached a maximum at 6-8 ° Baumé in the Airén grapes and at around 11 ° Baumé in the Chardonnay and Macabeo grapes.

Download Full-text

THE COLORIMETRIC DETERMINATION OF PLATINUM WITH 5-(p-DIMETHYLAMINOBENZYLIDENE)-RHODANINE

Canadian Journal of Chemistry ◽

10.1139/v63-094 ◽

1963 ◽

Vol 41 (3) ◽

pp. 667-670 ◽

Cited By ~ 13

Author(s):

Frances E. Piercy ◽

D. E. Ryan

Keyword(s):

Ascorbic Acid ◽

The Other ◽

Colorimetric Determination ◽

Platinum Metals ◽

Low Concentrations ◽

Fold Excess

5-(p-Dimethylaminobenzylidene)-rhodanine is used to determine 0.5 to 6 p.p.m. of platinum colorimetrically, after reduction of platinum IV with ascorbic acid. Platinum can be determined in the presence of a 10-fold excess of palladium; low concentrations of the other platinum metals, except rhodium, do not seriously interfere.

Download Full-text

Effect of grape variety (Vitis vinifera L.) and grape pomace fermentation conditions on some volatile compounds of the produced grape pomace distillate

OENO One ◽

10.20870/oeno-one.2004.38.4.912 ◽

2004 ◽

Vol 38 (4) ◽

pp. 225 ◽

Cited By ~ 1

Author(s):

Maria Gerogiannaki-Christopoulou ◽

Nikolaos V. Kyriakidis ◽

Panagiotis E. Athanasopoulos

Keyword(s):

Citric Acid ◽

Vitis Vinifera ◽

Volatile Compounds ◽

Internal Standard ◽

Grape Pomace ◽

Grape Variety ◽

Ionization Detector ◽

Flame Ionization ◽

Grape Varieties

Agrape pomace distillate was produced from 4 Greek white grape varieties (Vitis vinifera L.). Pomace was fermented with and without addition of citric acid, acting as an antibacterial agent, during fermentation. Fermented grape pomace was distilled in a traditional copper distillation apparatus.. Five major volatile compounds, including methanol, were measured. Pentanol-3 was used as an internal standard. Flame ionization detector (FID) coupled to capillary gas chromatography was used for determination of five volatile distillate components. The addition of citric acid resulted in the reduction of methanol content by about 15%. All the other components studied did not affect in any appreciable degree.

Download Full-text

Determination of caffeine content and the volatile compound in some products of roasted and instant coffee in Vietnam

Science and Technology Development Journal ◽

10.32508/stdj.v18i2.1062 ◽

2015 ◽

Vol 18 (2) ◽

pp. 85-93

Author(s):

Quyen Phuong Nguyen ◽

Tuyet Thi Ngoc Nguyen ◽

Phung Thi Kim Le ◽

Quan Thanh Pham

Keyword(s):

Volatile Compounds ◽

Supercritical Fluid Extraction ◽

Supercritical Fluid ◽

Volatile Compound ◽

Fluid Extraction ◽

Roasted Coffee ◽

Instant Coffee ◽

Caffeine Content

The aims of this study was to evaluate the quality of coffee in Vietnam market.Two methods Soxhlet and supercritical fluid extraction (SFE) were used to investigate the content of caffeine in 15 coffee samples; in which, 8 sample of roasted coffee and 7 sample of instant coffee. –The content of caffeine in 15 samples was different, and dependent on the object of the manufactures; caffeine is in charge of contribution of bitter and alert for customers. The content of caffeine was about 0.3% - 1.79% for the roasted coffee and 0.32% - 0.88% for the instant coffee. This study was also found out the method to extract the volatile compounds by using SDE and SPME. The major volatile compounds were pyrazine, furan, pyrrole, and pyridine. The number of the volatile compounds was 45 and 49 for SDE and SPME, respectively.

Download Full-text

Phytochemical screening and analysis of heavy metals of Nerium oleander (L.) leaves

Mediterranean Journal of Chemistry ◽

10.13171/mjc10402004201366aa ◽

2020 ◽

Vol 10 (4) ◽

pp. 346

Author(s):

Jamila Fliou ◽

Ouassima Riffi ◽

Ali Amechrouq ◽

Mohammed Elhourri ◽

Mostafa El Idrissi ◽

...

Keyword(s):

Absorption Spectrometry ◽

Scientific Data ◽

The Other ◽

Nerium Oleander ◽

Phytochemical Screening ◽

Low Concentrations ◽

Anthracene Derivatives ◽

Harmful Effects ◽

Pb Concentration

The main objective of this research is studying phytochemical screening of the extracts of polluted Nerium oleander (L.), and unpolluted Nerium oleander (L.) collected from Meknes region (Morocco), and determination of metals concentration that can have harmful effects on human health. In addition, the study provides scientific data.Studies have shown that the two extracts of polluted Nerium oleander (L.) and unpolluted Nerium oleander (L.) plant are rich in flavonoids, catechic and gallic tannins. In contrast, anthracene derivatives and flavonoids are absent. On the other hand, the comparative analysis of the results of atomic absorption spectrometry showed that the two plants of polluted Nerium oleander (L.) and unpolluted Nerium oleander (L.) contain a fairly high content of Na, Ca and Mg while the Pb concentration has exceeded the standard given by the WHO. While lithium and iron are present in low concentrations.

Download Full-text

Determination of the lattice translation across {110} APBs in GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105060 ◽

1988 ◽

Vol 46 ◽

pp. 600-601

Author(s):

D.R. Rasmussen ◽

N.-H. Cho ◽

C.B. Carter

Keyword(s):

Grain Boundaries ◽

Lower Energy ◽

Antiphase Boundary ◽

The Other ◽

Boundary Structure ◽

Interface Plane ◽

Inversion Symmetry ◽

High Angle ◽

Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Download Full-text

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108799 ◽

1978 ◽

Vol 36 (1) ◽

pp. 330-331

Author(s):

Y. Ishida ◽

H. Ishida ◽

K. Kohra ◽

H. Ichinose

Keyword(s):

High Order ◽

Simulation Technique ◽

The Other ◽

Image Simulation ◽

Diffraction Vector ◽

Burgers Vector ◽

Weak Beam ◽

Beam Image ◽

Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Download Full-text

Procedures for the Quantitative Determination of Autoprothrombin C

Thrombosis and Haemostasis ◽

10.1055/s-0038-1655441 ◽

1962 ◽

Vol 08 (03) ◽

pp. 434-441 ◽

Cited By ~ 3

Author(s):

Edmond R Cole ◽

Ewa Marciniak ◽

Walter H Seegers

Keyword(s):

Quantitative Determination ◽

Plasma Sample ◽

Quantitative Measure ◽

The Other ◽

Clotting Time ◽

Bovine Plasma ◽

Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

Download Full-text

Determination of Factor XIII Activity and of Factor XIII Inhibitors Using an Ammonium-Sensitive Electrode

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665256 ◽

1983 ◽

Vol 50 (02) ◽

pp. 563-566 ◽

Cited By ~ 3

Author(s):

P Hellstern ◽

K Schilz ◽

G von Blohn ◽

E Wenzel

Keyword(s):

Factor Xiii ◽

Normal Subjects ◽

The Other ◽

Activity Measurement ◽

Factor Xiii Deficiency ◽

Assay Procedure ◽

Stabilization Factor ◽

Release Method ◽

Sensitive Electrode

SummaryAn assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 ± 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the “ammonium-release-method”, Bohn’s method, and the immunological assay (r1 = 0.65; r2= 0.70; p<0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

Download Full-text