Search results for "chemical analysis"
showing 10 items of 324 documents
Sensory and chemical characterisation of Sauvignon blanc wine: Influence of source of origin
2011
Abstract The main objective of the study was to investigate influence of geographical location on volatile composition and perceived flavour profile of Sauvignon wines of New Zealand (Marlborough), French (Sancerre; Loire; Saint Bris), and Austrian (Styria) origin. Nineteen New Zealand wine professionals evaluated 18 Sauvignon wines, 6 from each source of origin, by sensory methods that included intensity ratings to experimenter-provided descriptors, typicality ratings, and classification tasks (non-directed and directed sorting). Results demonstrated that wines from the three sources of origin were separated by sensory analyses, with New Zealand wines dominated by perceived green character…
Proton Dynamics in In:BaZrO3: Insights on the Atomic and Electronic Structure from X-ray Absorption Spectroscopy
2009
The local structure of Ba2+, Zr4+, and In3+ in In:BaZrO3 is investigated with EXAFS for samples having 0 to 75% In3+ content. It is found that indium can be inserted in any ratio in the host matrix oxide and that the oxygen coordination shell displays an In-O distance very similar to the Zr-O length. In the Zr-rich compositions, there is a preferred dopant-vacancy association that, however, does not give rise to dopant-proton interaction in the hydrated samples. The tendency of Ba2+ to be attracted toward the dopant site is attributed to the electrostatic interaction with the dopant and to the structural rearrangement around the In3+ site. Third cumulant analysis at high temperatures (up to…
Raman investigation of the drawing effects on Ge-doped fibers
2011
International audience; We have investigated the Raman activity of various germanosilicate fibers and their associated preforms. Our data indicate an enhancement in small rings' (3-member rings) concentration in the silica-based matrix of the fibers during the drawing process. The generation of such rings appears compatible with an increase of the sample density and fictive temperature. The data regarding the drawing effects on the fiber stress appear less clear, and it is possible to suggest that in some cases the drawing could lower the tensile stress. Finally we have also provided evidence that changing the drawing conditions within the usual range of application leads to no significant …
Micro-Raman investigation of X or gamma irradiated Ge doped fibers
2011
International audience; Micro-Raman spectra have been recorded on Ge doped optical fibers before and after 10 keV-X or c-ray irradiation up to doses of 1 MGy (X-ray) or 7.8 MGy (-ray). Our data provide evidence that, at such dose levels, the glass matrix is not modified in a detectable way. We observed that varying the Ge doping levels from 0 to about 11 wt.%, X or radiation sensitivity of the overall matrix remains unchanged. Such results are observed for fibers obtained with drawing conditions within the usual range used for the fabrication of specialty fibers as radiation-tolerant waveguides. Our data support the potentiality of fiberbased sensors using glass properties, e.g. Raman sc…
Ocena ścieków browarnianych w wybranych punktach linii technologicznej
2016
Źródłem ścieków browarnianych są: warzelnia, fermentownia, leżakownia, rozlewnia oraz miejsce mycia opakowań. W zależności od etapu produkcyjnego ścieki te cechują zróżnicowane parametry mikrobiologiczne i fizykochemiczne. Ze względu na dużą zawartość substancji organicznych mogą one stanowić pożywkę dla różnych grup mikroorganizmów. Celem badań była ocena mikrobiologiczna ścieków browarnianych w trzech różnych punktach linii technologicznej ze szczególnym uwzględnieniem obecności mikroorganizmów potencjalnie chorobotwórczych. Materiał badawczy stanowiły ścieki pobrane z komór zbierających ścieki 1 i 2 oraz kolektora przy wylocie do rzeki. Badania mikrobiologiczne obejmowały oznaczenia ogól…
Strength of cellulosic fiber/starch acetate composites with variable fiber and plasticizer content
2014
In this experimental study, the performance of injection-molded short flax and hemp fibers in plasticized starch acetate were analyzed in terms of strength. Parameters involved in the analysis are a variable fiber and plasticizer content. The measured strength of the composites varies in the range of 12–51 MPa for flax fibers and 11–42 MPa for hemp fibers, which is significantly higher than the properties of the unreinforced starch acetate matrix. The micro-structural parameters used in modeling of composite strength were obtained from optical observations and indirect measurements. Some of these parameters were qualitatively verified by X-ray microtomography.
An inter-laboratory comparison to evaluate the suitability of EN 1787 standard to detect irradiation in plant-origin foods with health benefits
2020
Abstract This paper reports the results of a study carried out to verify the applicability of the EN 1787 method, which uses the Electron Spin Resonance (ESR) technique for the identification of irradiated plant-origin foods with health benefits. The method was tested on samples of herbal ingredients of Plant Food Supplements (PFSs), nuts and fresh blueberries. Untreated and irradiated samples of Camellia sinensis (leaves) Ginkgo biloba (leaves), Glycine max (seeds), Silybum marianum (fruits), Vaccinium myrtillus (fruits), almonds, hazelnuts, peanuts, pistachios, walnuts and fresh blueberries were analysed. The work includes an inter-laboratory blind test involving five Italian laboratories…
Pulsed Electric Field Processing Optimization of Ascorbic Acid in a Mango and Papaya Beverage Sweetened with Stevia Rebaudiana
2016
During the processing of liquid foods, ascorbic acid may be altered, thus reducing beneficial health effects. For this reason, the degradation kinetics of ascorbic acid were determined in a fruit juice mixture (papaya and mango) sweetened with Stevia rebaudiana (SR) infusion after treatment by pulsed electric field (PEF) processing. The variable ranges were 20-40 kV/cm (electric field strength, E) during 100-360 μs (time treatment, t). The degradation equation was AA (mg/100 mL) = 26.842 - 0.101·E - 0.003·t- 10.371·%Stevia + 2.865·%Stevia2, demonstrating the use of PEF as an alternative to pasteurization treatments. However, results show the need to optimize treatment conditions whenever th…
Instrumental and sensory evaluation of eating quality of peaches and nectarines
2012
The influence of flesh firmness on consumer acceptance and its relationship with total soluble solids (TSS), titratable acidity (TTA) and sensory analysis were studied for fruits of ‘September Sun’ and ‘Sweet September’ (low acid) peach (Prunus persica (L.) Batsch), and ‘Maria Dolce’ (low acid) and ‘Venus’ nectarine (Prunus persica (L.) Batsch, var. nucipersica) cultivars. Sensory descriptors, assessed by a short-trained panel, were firmness, sweetness, sourness, aroma, acceptability. Different stages of fruit firmness did not always result in significant differences of TSS, TTA and their ratio, but the panel was able to discriminate fruit ripening stages, in terms of fruit firmness, aroma …
Analysis of Contact Traces of Cannabis by In-Tube Solid-Phase Microextraction Coupled to Nanoliquid Chromatography
2018
Because of its inherent qualities, in-tube solid-phase microextraction (IT-SPME) coupled on-line to nanoliquid chromatography (nanoLC) can be a very powerful tool to address the new challenges of analytical laboratories such as the analysis of traces of complex samples. This is the case of the detection of contact traces of drugs, especially cannabis. The main difficulties encountered in the analysis of traces of cannabis plants on surfaces are the low amount of sample available (typically <