1,720,998 research outputs found
Analysis of Apple Flavours: The Use of Volatile Organic Compounds to Address Cultivar Differences and the Correlation between Consumer Appreciation and Aroma Profiling
No full textIn the selection of apple (Malus domestica Borkh) fruits, consumers predominantly use visual and organoleptic responses, such as aroma and texture, as quality/preference markers. Previous studies profiling the sensory properties and aroma profiles of apple varieties have provided a lexicon describing important attributes within the modalities of aroma, texture, and flavour. The range of volatile organic compounds (VOCs) produced by four apple cultivars was assessed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). To facilitate automated dynamic headspace extraction of the VOCs from bulk samples, a small multichamber thermal extraction system was used. Forty compounds were detected and putatively identified by mass spectral comparison with NIST libraries. Eight compounds were not previously identified in apples. Permutational multivariate analysis of variance (PerMANOVA) and canonical analysis of principal coordinates (CAP) done on the whole volatile organic compound profiles show separation of the four cultivars. The use of random forest classification enabled the determination of a minimum set of fifteen potential VOC markers that successfully differentiate the cultivars under study. Trends across samples, VOCs, and sensory evaluation are revealed. The association between 4-hexen-1-ol acetate with texture/consistency, and crispiness, and correlation of 2-methylbut-2-en-1-yl acetate with juiciness and acidity is shown for the first time. These sensory correlations indicate that the compounds determined by this experiment could be used as objective markers for the consumer appreciation of fresh apples, enabling the optimum conditions for processing and storage of individual cultivars to be identified without recourse to expensive sensory panels in every case. Such tests could also be used as part of routine quality control by the producer and retailer, reducing costs and eliminating waste due to batches of inferior product
Developmental stimuli and stress factors affect expression of ClGLP1, an emerging allergen-related gene in Citrus limon.
No full textbe involved in many developmental and stress related processes. A novel GLP cDNA was isolated from
Citrus limon and structural features and genomic organization were investigated by in silico and Southern
blots analysis. In lemon, the ClGLP1 encodes a 24.38 kDa which possesses a conserved motif of plant GLPs
proteins. A phylogetic analysis mapped ClGLP1 as belonging to the GER3 subfamily into the GLP1 group of
large GLP family. ClGLP1 was differentially expressed in the various organs and was highest in mature
fruit. Moreover, expression in the fruit was tissue- and stage-related as well as dependent on agricultural
practice (organic vs conventional). ClGLP1 transcripts increased during the transition from the green (180
days after blooming) to the yellow (240 days after blooming) mature fruit and were strongly enhanced in
yellow mature fruit from organic compared with conventional culture. A sudden and systemic increase in
ClGLP1 expression level was observed in leaves injured by wounding, together with an increase of
endogenous H2O2 amount. Notably, an enhancement of H202 was observed in fruit peel during transition
from green to yellow fruit stage. All together our data showed that ClGLP1 expression can be modulated
in relation to both developmental stimuli and culture practices; evidence is also provided that through
an oxidase activity this gene could play a role in fruit maturation as well as in stress responses
Scents and scentsitivity - what scents (may) spell out and ways to read it
No full textChemically, scent marks and natural flavours mostly consist of complex mixtures of chemical compounds,which are neither easily recorded nor interpreted. The facts that the size of a signal in the chemical detection(mass spectrometer) does not necessarily relate to the size in perceptual space and that a signal can just as well be encoded as bouquet of compounds than depending on presence and absence of multiple or single components complicate matters even further. In a recent project on European otters and an ongoing EU project on fruit and vegetable flavours we addressed these issues by using novel approaches in data evaluation and sample collection and data acquisition
Combining Thermal Desorption GC and TOF-MS for the Determination of Melon VOC Profiles
No full textThe quality and safety of ready-to-eat packaged foods—such as salads—is very difficult for
consumers and suppliers to judge, and improving this situation is the focus of a Europe-wide
research project. Part of the project is devoted to the development of better methods to detect
and analyze the volatile organic compounds released from relevant food types, in an effort to
identify biomarkers for quality and microbial contamination. This article examines one important
food—melon—and shows how a method based on thermal desorption with gas chromatography–
time-of-flight mass spectrometry (GC–TOF-MS) can elucidate how key volatiles vary
with the size of the melon pieces. The article highlights how such analytical information will be
of value in efforts to improve the quality and safety of ready-to-eat foods
Multi-Omic Approaches to Investigate Molecular Mechanisms in Peach Post-Harvest Ripening
No full textPeach post-harvest ripening is a complex developmental process controlled by a plethora of genetic and epigenetic factors. Specifically, it leads to protein, lipid and nucleic acid degradation, all resulting in cell death. Substantial research has been directed at investigating peach regulatory mechanisms underlying genomic, metabolomic and transcriptomic modifications occurring during this stage, and much progress has been made thanks to the advent of Next Generation Sequencing technologies. This review is focused on the latest multi-omics studies, with the aim of highlighting the most significant results and further investigating the regulation of the key genes involved in peach post-harvest processes and related physiology. By offering an exhaustive overview of peach omics profiles, it provides a comprehensive description of gene expression changes and their correlation with ripening stages, including some post-harvest treatments, as well as with volatile organic compound modifications. However, the present work highlights that, due to the complexity of the process, recent investigations do not elucidate all underlying molecular mechanisms, making further studies still necessary. For this reason, some key points for future research activities and innovative peach breeding programs are discussed, relying on trusted multi-omic approaches
Exploring multiple-cumulative trapping solid-phase microextraction coupled to gas chromatography–mass spectrometry for quality and authenticity assessment of olive oil
No full textThis study explores the potential of an innovative multi-cumulative trapping headspace solid-phase microextraction approach coupled with untargeted data analysis to enhance the information provided by aroma profiling of virgin olive oil. Sixty-nine samples of different olive oil commercial categories (extra-virgin, virgin and lampante oil) and different geographical origins were analysed using this novel workflow. The results from each sample were aligned and compared using for the first time a tile-based approach to enable the mining of all of the raw data within the chemometrics platform without any pre-processing methods. The data matrix obtained allowed the extraction of multiple-level information from the volatile profile of the samples. Not only was it possible to classify the samples within the commercial category that they belonged to, but the same data also provided interesting information regarding the geographical origin of the extra-virgin olive oil
Use of TD-GC–TOF-MS to assess volatile composition during post-harvest storage in seven accessions of rocket salad (Eruca sativa). BELL L, SPADAFORA D.N. contributed equally to the work
No full textAn important step in breeding for nutritionally enhanced varieties is determining the effects of the postharvest
supply chain on phytochemicals and the changes in VOCs produced over time. TD-GC–TOF-MS
was used and a technique for the extraction of VOCs from the headspace using portable tubes is
described. Forty-two compounds were detected; 39 were identified by comparison to NIST libraries.
Thirty-five compounds had not been previously reported in Eruca sativa. Seven accessions were assessed
for changes in headspace VOCs over 7 days. Relative amounts of VOCs across 3 time points were significantly
different – isothiocyanate-containing molecules being abundant on ‘Day 0’. Each accession
showed differences in proportions/types of volatiles produced on each day. PCA revealed a separation
of VOC profiles according to the day of sampling. Changes in VOC profiles over time could provide a tool
for assessment of shelf life
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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