1,721,190 research outputs found
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
Phenotyping methods to assess heat stress resilience in grapevine
No full textGlobal warming has become an issue in recent years in viticulture, as increasing temperatures have a negative impact on grapevine (Vitis vinifera) production and on wine quality. Phenotyping for grapevine response to heat stress is, therefore, important to understand thermotolerance mechanisms, with the aim of improving field management strategies or developing more resilient varieties. Nonetheless, the choice of the phenotypic traits to be investigated is not trivial and depends mainly on the objectives of the study, but also on the number of samples and on the availability of instrumentation. Moreover, the grapevine literature reports few studies related to thermotolerance, generally assessing physiological responses, which highlights the need for more holistic approaches. In this context, the present review offers an overview of target traits that are commonly investigated in plant thermotolerance studies, with a special focus on grapevine, and of methods that can be employed to evaluate those traits. With the final goal of providing useful tools and references for future studies on grapevine heat stress resilience, advantages and limitations of each method are highlighted, and the available or possible implementations are described. In this way, the reader is guided in the choice of the best approaches in terms of speed, complexity, range of application, sensitivity, and specificity
Validation of a functional molecular marker suitable for marker-assisted breeding for fruit texture in apple (Malus × domestica Borkh.)
No full textMolecular markers are nowadays considered fundamental tools in breeding programs, supporting the selection of the most favourable offspring. This role is invaluable in the case of complex agronomic traits in tree fruit crop species, such as fruit texture in apple (Malus × domestica Borkh.). This work presents the validation of a previously identified functional simple sequence repeat marker, named Md-PG1SSR10kd, suitable for the advanced selection of high texture performance seedlings. Two independent populations were chosen by marker-assisted parent selection, and a specific set of seedlings was selected by marker-assisted seedling selection, to validate the predictive power of this marker. The two groups of seedlings, further phenotyped for fruit texture, showed a clear difference in texture behaviour. The selection of this marker also showed a higher efficiency than Md-ACS1 and Md-ACO1, two functional markers currently implemented in different breeding programs. Finally, the allelic effect was estimated by computing the breeding values in a collection of 83 different apple cultivars. The results reported here confirmed the association of Md-PG1SSR10kd with texture sub-traits, proposing this as a novel promising selection strategy suitable for apple fruit textur
High-throughput screening for in planta characterization of VOC biosynthetic genes by PTR-ToF-MS
Full text linkFunctional characterization of plant volatile organic compound (VOC) biosynthetic genes and elucidation of the biological
function of their products often involve the screening of large numbers of plants from either independent transformation
events or mapping populations. The low time resolution of standard gas chromatographic methods, however, represents a
major bottleneck for in planta genetic characterization of VOC biosynthetic genes. Here we present a fast and highly-sensitive
method for the high-throughput characterization of VOC emission levels/patterns by coupling a Proton Transfer Reaction
Time-of-Flight Mass Spectrometer to an autosampler for automation of sample measurement. With this system more than
700 samples per day can be screened, detecting for each sample hundreds of spectrometric peaks in the m/z 15–300 range.
As a case study, we report the characterization of VOC emissions from 116 independent Arabidopsis thaliana lines transformed
with a putative isoprene synthase gene, confirming its function also when fused to a C-terminal 3×FLAG tag. We
demonstrate that the method is more reliable than conventional characterization of transgene expression for the identification
of the most highly isoprene-emitting lines. The throughput of this VOC screening method exceeds that of existing alternatives,
potentially allowing its application to reverse and forward genetic screenings of genes contributing to VOC emission,
constituting a powerful tool for the functional characterization of VOC biosynthetic genes and elucidation of the biological
functions of their products directly in planta
First characterisation of herbivore-induced volatiles released by grapevine (cv. Pinot noir) under attack of Empoasca vitis (Hemiptera: Cicadellidae)
No full textEnhancement of the pH measurement of a PVDF-supported colorimetric sensor by tailoring hue changes with the addition of a second dye
No full textA pH colorimetric sensor was prepared and characterized by combining two acid-base indicators, Tetrabromophenol blue (TBB) and Phenol Red (PR) with molar ratios ranging from 0 to 0.47. Indicators were embedded in Organically Modified Silicate (OrMoSil) spots supported in Polyvinylidene fluoride (PVDF) together with a suitable cationic surfactant. The deposition procedure was very repeatable allowing a single calibration for all membranes built in the same preparation lot. The signal was based on the Hue profile (H) vs. pH. The CIE-xy color space contains an achromatic point that is the key point of the colorimetric sensor behavior as it causes the inversion of the slope of the H calibration curve at a specific inversion point. For this reason, the identification of the effective conditions of the improvement of the PR analytical performances are not trivial, 0.186 < nTBB/nPR < 0.324 with prediction error in the range 0.01–0.16 pH unit. The proposed adjustment allowed the construction of pH colorimetric sensors with prediction error comparable to that of potentiometric measurements. The obtained results indicated the route to widen the availability even to those acid-base indicators lacking of suitable color transitions but having suitable pKa values
A mechanism for biogenic production and emission of MEK from MVK decoupled from isoprene biosynthesis
No full textMethyl ethyl ketone (MEK) is an important compound in atmospheric chemistry. While attention has been paid mostly to anthropogenic sources of MEK, recently it has been shown that biogenic sources are globally as important as anthropogenic ones. However, the origin of biogenic MEK has yet to be completely elucidated. We present the full mechanism by which within-plant transformation of methyl vinyl ketone (MVK) and, to a minor extent, of 2-butanol and 3-buten-2-ol, is a source of biogenic MEK. Such transformation is observed in red oak for both exogenous MVK, taken up from the atmosphere, and endogenous MVK generated within a plant when it experiences stress (e.g. heat stress). Endogenous MVK emitted by plants is typically explained by within-plant oxidation of isoprene caused by oxidative stress. In this study we show that MVK and MEK emissions caused by heat stress are not related to isoprene in isoprene-emitting plants, implying that the massive carbon investment that plants commit to isoprene production is not explained by a direct antioxidant role. The presented mechanism can be important for inclusion in plant emission and in plant-atmosphere interaction models
The good, the bad and the aged: quality control of anhydrous milk fat by Proton Transfer Reaction Mass Spectrometry
Full text linkPTR-MS (Proton Transfer Reaction Mass Spectrometry) is an accurate, high sensitivity, direct-injection technique that allows for the rapid characterization of food products and for the monitoring of processes in food science and agro-industry, without any pre-treatment [1]. In the last years, the importance of this technology in food research has increased quickly and it has been applied to address different issues as the monitoring of volatile organic compound (VOCs) emission during time (e.g. shelf life or processing) and the rapid classification of food samples according, e.g., to quality or geographical origin [2].
This study aims at verifying whether rapid and direct headspace PTR-MS analysis can correctly classify anhydrous milk fat (AMF) samples according to classes defined by sensory analysis or accelerated shelf-life. 39 samples were divided in three classes (OK, BAD, AGED) according to sensory evaluation by 7 to 12 trained panelists (OK, BAD) or thermal treatment (AGED). Five replicates of each sample were then measured through PTR-ToF-MS for a total of about 200 measurements. Measurements were performed in an automated way using a multipurpose GC automatic sampler (Gerstel GmbH, Mulheim am Ruhr, Germany) connected to the inlet of a commercial PTR-ToF-MS 8000 instrument (Ionicon Analytik GmbH, Innsbruck, Austria). PTR-MS data were then extracted [3, 4]. Principal component analysis (PCA) was performed on the dataset of mass peaks belonging to AMF samples significantly different from blank samples (1-way ANOVA with Boneferroni correction, p.value <0.01). The analysis lead to a clear separation of the three different classes of AMF samples. PLS-DA was then performed to build a discrimination model. The correct classification with an exception of only one sample was obtained from the dataset contained all mass peaks.
This pilot study indicate that PTR-ToF-MS can be implemented as a rapid (less than 60 s per measurement) and efficient tool for anhydrous milk fat quality control in agroindustry.
References:
1. Biasioli, F., et al., PTR-MS monitoring of VOCs and BVOCs in food science and technology. Trac-Trends in Analytical Chemistry, 2011. 30(7): p. 968-977.
2. Ellis, A.M. and C.A. Mayhew, PTR-MS in the Food Sciences, in Proton Transfer Reaction Mass Spectrometry. 2014, John Wiley & Sons, Ltd. p. 221-265.
3. Lindinger, W., A. Hansel, and A. Jordan, On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS) - Medical applications, food control and environmental research. International Journal of Mass Spectrometry, 1998. 173(3): p. 191-241
Evaluation of PTR-MS analysis as rapid and non invasive tool for quality control in agroindustry: the effect of storage and packaging on anhydrous milk fat
No full textThe growing awareness of consumers for food quality posed new challenges to the quality control (QC) programs of agroindustry. The reliability in sensory and performance experiences of a product has been recognized as an important feature of product quality [1]. Thus, assuring the quality of products on a sensory basis is a fundamental corporate goal. However, sensory analysis, due to its high costs in terms of both time and resources, is not always feasible and adaptable to the high number of samples and fast decision times required by industry [2]. To answer to these needs, new rapid and non-invasive instrumental methods have been developed in the last years. Among the different approaches, analyzing the volatile organic compounds (VOCs) of the different matrixes seems the most promising since VOCs have a key-role in defining food flavor and aroma [3]. For long time gas chromatography (GC) has been the reference method but in the last years, new direct injection mass spectrometry methods have been developed in order to improve time resolution leading to high sensitive and faster analysis.
Proton-transfer reaction mass spectrometry (PTR-MS) is one of these techniques. Based on proton transfer from a protonated reagent, usually H3O+, it implements efficiently a soft chemical ionization that makes this technique suitable for rapid characterization of food products [3].
PTR-MS and other techniques have been widely used in different researchers to investigate the different flavors and off-flavors originating from dairy ingredients leading to the identification of more than 230 VOCs [4-6]. The aim of this research was to evaluate PTR-MS as a rapid tool for the quality control of anhydrous milk fat (AMF). AMF usage in pastry, confectionery and ice-cream industry, is rapidly increasing due to its convenient features. The effect of different type of packaging – Bag-in-Box (BIB) and cardboard packages with a layer of plastic film (CT) – on the volatile profile and the quality of AMF has been investigated during a shelf life of 8 months at refrigerated storage (4°C). AMFs were valuated both during shelf life and accelerated shelf life (ASL) where AMF was exposed at 50°C for a total of 11 days
High-Throughput Quantification of Trace Haloanisole and Halophenol Off-Flavor Compounds in Cork Wine Stoppers
No full textA high-throughput, nondestructive quantification solution for the trace analysis of haloanisole and halophenol off-flavor compounds in cork wine stoppers based on chemical ionization time-of-flight mass spectrometry is presented. Using a fully automated workflow, individual cork stoppers can be measured continuously with a sample-to-sample time of less than 3 s, with limits of quantification in the range of 0.1 ng/L for all target compounds. This approach allows comprehensive, quality control of cork stopper production while at the same time opening new possibilities for research on the origin of off-flavors in natural matrices
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