1,721,328 research outputs found
Volatile compound changes during shelf life of dried Boletus edulis: comparison between SPME-GC-MS and PTR-ToF-MS analysis
Full text linkThe purpose of our study was the investigation of the evolution of volatile compounds in dehydrated porcini mushroom during the shelf life. Although considered a stable product dried porcini flavour changes during storage. The study was developed in collaboration with a local distributor of dried mushrooms, interested to know more about its product during the commercial shelf life (up to 12 months) and evaluate new methods to assist quality control and product development
Special Issue "Volatile Compounds and Smell Chemicals (Odor and Aroma) of Food"
Full text linkAmong the constituents of food, volatile compounds are a particularly intriguing group of molecules, because they give rise to odour and aroma [...
Effect of the pig rearing system on the final volatile profile of Iberian dry-cured ham as detected by PTR-ToF-MS
Full text linkThe volatile compound profile of dry-cured Iberian ham lean and subcutaneous fat from pigs fattened outdoors on acorn and pasture (Montanera) or on high-oleic concentrated feed (Campo) was investigated by proton transfer reaction time-of-flight mass spectrometry. In addition to the usual proton transfer ionization we implemented the novel switchable reagent ions system which allows the use of different precursor ions (H3O+, NO+ and O2+). The analysis of the lean and subcutaneous fat volatile compounds allowed good sample discrimination according to the diet. Differences were evident for several classes of compounds: in particular, Montanera hams showed higher concentrations of aldehydes and ketones and lower concentrations of sulfur-containing compounds compared to Campo hams. The use of NO+ as precursor ion confirmed the results obtained with H3O+ in terms of classification capability and provides additional analytical insights.Fil: Sanchez del Pulgar, J.. Fondazione Edmund Mach. Research and Innovation Centre; Italia. Universidad de Extremadura. Facultad de Veterinaria; ArgentinaFil: Soukoulis, S.. Fondazione Edmund Mach. Research and Innovation Centre; ItaliaFil: Carrapiso, A. I.. Universidad de Extremadura. Escuela de Ingenierías Agrarias; EspañaFil: Cappellin, L.. Fondazione Edmund Mach. Research and Innovation Centre; ItaliaFil: Granitto, Pablo Miguel. Universidad Nacional de Rosario; ArgentinaFil: Aprea, E.. Fondazione Edmund Mach. Research and Innovation Centre; ItaliaFil: Romano, A. Fondazione Edmund Mach. Research and Innovation Centre; ItaliaFil: Gasperini, F.. Fondazione Edmund Mach. Research and Innovation Centre; ItaliaFil: Biasioli, F.. Fondazione Edmund Mach. Research and Innovation Centre; Itali
Nosespace analysis by PTR-ToF-MS for the extravirgin olive oil characterization
No full textIntroduction:
Extravirgin olive (EVO) oil aroma and taste influence consumer preferences. Volatile organic compounds (VOCs) release from food within oral cavity is a complex process. Nose-space (NS) analysis should unravel the retro-nasal olfaction processes happened during olive oil tasting. Proton Transfer Reaction-Mass Spectrometry with Time-of-Flight analyser (PTR-ToF-MS) was already successfully applied for NS analysis of apples [2], cereal bars [3], coffee [4,5].
Methods:
In this study 2 Italian EVO oils were used: commercial vs home made (Lago di Garda, TN). Pure oil, oil mixed with tomato sauce, oil on bread prepared for each EVO oil were used for headspace (HS) and NS measurements by PTR-ToF-MS 8000. The samples were presented to 8 assessors in duplicate. For NS sampling a glass nose-piece with silicone rubber tube was fitted into assessors’ nostrils and connected to PTR-ToF-MS. The method for HS analysis was described elsewhere [6].
Results:
26 out of 319 mass peaks of NS dataset displayed signal related to olive oil, tomato or bread aroma. Peaks related to human metabolism were eliminated. The individual profiles differed in peak intensity and duration. However it was possible to distinguish the two types of EVO oils. HS data confirmed diversity of the oils. Home-made EVO oil in all products was characterized by significantly higher concentrations of mass peak 99.081 tentatively identified (t.i.) as (E)-2-hexenal associated to a green-leaf and fruity flavor [1]. Commercial EVO oil was richer in t.i. pentanal, acetic acid, butanal, and several esters which are reported as oxidation products of olive oil [7]. The samples of olive oil on bread showed the best performance (higher signals intensities) for all panellists due to an increased release surface area, prolonged presence in mouth, increased interaction with saliva and mucosal surfaces. Adding tomato sauce to olive oil decreased the olive oil aroma release in NS and contaminated it with tomato aroma.
Conclusions
NS analysis performed by PTR-ToF-MS discriminated different EVO olive oils. HS and NS data were consistent. The next steps are the optimization of sample preparations, tasting protocol, and the improvement of PTR-ToF-MS sensitivity by applying an ion funnel.
The optimized methods will be applied to study different EVO olive oils within the project “VIOLIN” aiming to the valorisation and promotion of Italian EVO oils.
Novel Aspect:
For the first time NS analysis was applied for olive oil profiling taking into consideration individual perception and the combination with different food matrices
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Refined measurements of Henry’s law constant of terpenes with inert gas stripping coupled with PTR-MS
No full textHenry’s law constant is an essential parameter for the estimation of the environmental prevalence of pollutants. Here, we present two improved methods for
measuring Henry’s law constant deploying inert gas stripping (IGS). The methods are targeted at compounds with high gamma coefficients (activity coefficient at
infinite dilution) corresponding to large infinite dilution coefficients, such as monoterpenes and sesquiterpenes.
We deploy a highly sensitive PTR-MS (proton transfer reaction-mass spectrometer) (low limit of detection, wide linear range, split-second time resolution) as detector.
We use suited off-equilibrium conditions to extrapolate to equilibrium conditions. The first method is based on the observed linear correlation between gas flow and off-equilibrium experimental Henry’s law constant value. The second method is based on the linear dependence of the gas holdup on volumetric flow. We report HLC constants for six monoterpenes, isoprene and even, as a proof of concept, the sesquiterpene
farnesene. The new methods allow for measuring HLC of nearly insoluble compounds at a new accuracy and precisio
- …
