371 research outputs found
Grape VOCs response to postharvest short-term ozone treatments
Ozone has been recently recognized as an efficient sanitizing agent in wine industry because of its powerful oxidizing properties. Furthermore, postharvest treatments of grapes with ozone can stimulate defense responses by synthetizing secondary metabolites against oxidative stress. In this study, the effect of postharvest short-term ozone treatments was assessed for the first time on free and glycosylated volatile organic compounds (VOCs) of winegrapes. Two different ozone concentrations (30 and 60 μL/L) and exposure times (24 and 48 h) were investigated just after treatment (fresh grapes) and after partial dehydration up to 20% weight loss (withered grapes). The study was carried out on Moscato bianco winegrapes (Vitis vinifera L.) due to the importance of terpenes in white aromatic cultivars to produce high quality wines. The results obtained showed that short-term ozone treatment caused a significant decrease in total contents of free VOCs in fresh grapes, mainly due to terpenes. Among them, linalool, geraniol, and nerol are the major aromatic markers of Moscato bianco grapes. Ozone entailed a significant decrease of free linalool contents in fresh grapes, the less stressful ozone treatment showing the smaller linalool degradation. However, the stronger and longer ozone treatment induced the synthesis of this compound probably in response to higher abiotic stress. Instead, significant changes were not observed in geraniol and nerol contents in fresh grapes. This last ozone treatment also reduced the loss of free linalool by water loss in withered grapes even though total VOCs and terpenes remained relatively stable. Furthermore, ozone seems to promote the synthesis of free (+)-4-carene and 4-terpineol in withered grapes under certain treatment conditions. Regarding glycosylated compounds, total VOCs and terpenes were less sensitive to ozone. Our findings highlight that ozone can be used as sanitizing agent in aromatic grape varieties prior to winemaking without affecting sharply the aromatic profile of fresh grapes and even improving it in withered grapes
Evolution of the Phenolic Content and Extractability Indices During Ripening of Nebbiolo Grapes from the Piedmont Growing Areas over Six Consecutive Years
The phenolic composition and extractability indices of grape berries play a key role in assessing redwine quality because the relationship between grape phenolic maturity and wine phenolic compositionis well known. In this work, grape quality indices were determined in Nebbiolo grapes from two growingareas of Langhe (South Piedmont), at different stages throughout the ripening process in six consecutiveyears (2004 to 2009), with the aim of evaluating the ripening- and growing area-related changes in thegrape indices separately. The effect of vintage was also investigated. Ripeness data were compared withanalogous data determined in Nebbiolo grapes grown in the Carema area (North Piedmont). The vintageeffect far outweighed any changes in the grape indices introduced by the ripening stage, even those arisingfrom differences in the production area. In the Langhe and Carema zones, the average berry mass, pH,total acidity, total anthocyanins extractable at pH 3.2, total flavonoids and non-anthocyanin flavonoidsextractable at pH 1, and the seed maturity index were seasonally dependent. The more ripening-affectedparameters were the technological ones. This work highlights the importance of determining the phenolextractability, since it provides relevant information that allows improved management of the macerationstage
Assessement of sensory firmness and crunchiness of table grapes by acoustic and mechanical properties.
Background and Aims The instrumental measurement of crunchiness in tablegrapes has been the subject of little research in spite of the great relevance of this sensory texture trait to consumer preference. Therefore, our aim was to evaluate the potential of several mechanical and acoustic properties to assess the perceived firmness and crunchiness of tablegrape cultivars. Methods and Results The ripening effect was minimised by densimetric sorting of the berries before testing. The textural quality of seven tablegrape cultivars was evaluated by sensory analysis. Furthermore, three mechanical tests (texture profile analysis, cutting and denture) were performed on the berry flesh or on whole berries, and the acoustic emission produced was recorded simultaneously. Correlation studies showed strong and significant relationships between sensory texture attributes and instrumental parameters, particularly for the denture test. Nevertheless, satisfactory predictive accuracy for the perceived crunchiness required multivariate linear regression involving both mechanical and acoustic properties resulting from the denture test performed on whole berries. In this case, residual predictive interquartile amplitude was higher than 2. Most of the reliable models developed for perceived firmness are fairly recommended not for quantitative purposes but for fast screening (1.6 < residual predictive interquartile amplitude < 2). Conclusions The standardised protocol proposed permits more objective and quantitative sensory data to be obtained for firmness and crunchiness of tablegrapes. Significance of the Study A combined mechanical–acoustic strategy has not previously been used in tablegrapes and represents a powerful tool for a more complete and exhaustive texture characterisation, particularly firmness and crunchiness, by means of a more objective and standardised protocol
Nanosponge-based composite gel polymer electrolyte for safer li-o2 batteries
Li-O2 batteries represent a promising rechargeable battery candidate to answer the energy challenges our world is facing, thanks to their ultrahigh theoretical energy density. However, the poor cycling stability of the Li-O2 system and, overall, important safety issues due to the formation of Li dendrites, combined with the use of organic liquid electrolytes and O2 cross-over, inhibit their practical applications. As a solution to these various issues, we propose a composite gel polymer electrolyte consisting of a highly cross-linked polymer matrix, containing a dextrin-based nanosponge and activated with a liquid electrolyte. The polymer matrix, easily obtained by thermally activated one pot free radical polymerization in bulk, allows to limit dendrite nucleation and growth thanks to its cross-linked structure. At the same time, the nanosponge limits the O2 cross-over and avoids the formation of crystalline domains in the polymer matrix, which, combined with the liquid electrolyte, allows a good ionic conductivity at room temperature. Such a composite gel polymer electrolyte, tested in a cell containing Li metal as anode and a simple commercial gas diffusion layer, without any catalyst, as cathode demonstrates a full capacity of 5.05 mAh cm−2 as well as improved reversibility upon cycling, compared to a cell containing liquid electrolyte
ENIGMA-A centralised supervisory controller for enhanced onboard electrical energy management with model in the loop demonstration
A centralised smart supervisor (CSS) controller with enhanced electrical energy management (E2-EM) capability has been developed for an Iron Bird Electrical Power Generation and Distribution System (EPGDS) within the Clean Sky 2 ENhanced electrical energy MAnagement (ENIGMA) project. The E2-EM strategy considers the potential for eliminating the 5 min overload capability of the generators to achieve a substantial reduction in the mass of the EPGDS. It ensures optimal power and energy sharing within the EPGDS by interfacing the CSS with the smart grid network (SGN), the energy storage and regeneration system (ESRS), and the programmable load bank 1 secondary distribution board (PLB1 SDU) during power overloads and failure conditions. The CSS has been developed by formalizing E2-EM logic as an algorithm operating in real time and by following safety and reliability rules. The CSS undergoes initial verification using model-in-the-loop (MIL) testing. This paper describes the EPGDS simulated for the MIL testing and details the E2-EM strategy, the algorithms, and logic developed for the ENIGMA CSS design. The CSS was subjected to two test cases using MIL demonstration, and based on the test results, the performance of the ENIGMA CSS is verified and validated
berry heterogeneity as a possible factor affecting the potential of seed mechanical properties to classify wine grape varieties and estimate flavanol release in wine like solution
Seed mechanical properties were instrumentally measured by compression testing in thirty white and red wine grape varieties at harvest. The effect of berry heterogeneity in a vineyard on these seed texture parameters was also evaluated to improve the understanding of intra-sample variability. Furthermore, the mechanical properties of the seeds were assessed as possible predictors of their phenolic extractability. The results show that the texture parameters of the seeds are independent of the location of the berry in the vineyard and the soluble solid content at harvest. Densimetric flotation of the berries permits the reduction of the intra-sample variability that could hinder the differentiation and/or classification of wine grape varieties according to seed mechanical attributes. Cluster analysis classified the wine grape varieties studied into three groups according to seed hardness (low: 32.51 to 40.80 N, intermediate: 42.84 to 44.99 N, high: 46.71 to 57.78 N). The relationships between the seed mechanical properties and the extractable content of phenolic compounds, determined by spectrophotometric and chromatographic reference chemical methods, were evaluated by means of correlation analysis. Linear regression calibration models were developed for each cluster. The statistical parameters highlighted that total flavonoids, proanthocyanidins and flavanols reactive to vanillin can be predicted successfully from the seed mechanical properties for the varieties having low and intermediate seed hardness (SEC% ca. 20, RPIQ > 1.6). For varieties with harder seeds, a satisfactory predictive accuracy seems to require the construction of separate calibration models for each cultivar (Nebbiolo, SEC% ca. 20, RPIQ > 2.2)
Ozone Improves the Aromatic Fingerprint of White Grapes
Ozone, a powerful oxidative stressor, has been recently used in wine industry as sanitizing agent to reduce spoilage microflora on grapes. In this study, we evaluated ozone-induced metabolic and molecular responses during postharvest grape dehydration. Ozone increased the contents of total volatile organic compounds (VOCs), which have a great impact on the organoleptic properties of grapes and wines. Among terpenes, responsible for floral and fruity aroma, linalool, geraniol and nerol were the major aromatic markers of Moscato bianco grapes. They were significantly affected by the long-term ozone treatment, increasing their concentration in the last phases of dehydration (>20% weight loss). At molecular level, our results demonstrated that both postharvest dehydration and ozone exposure induce the biosynthesis of monoterpenes via methylerythritol phosphate (MEP) pathway and of aldehydes from lipoxygenase-hydroperoxide lyase (LOX-HPL) pathway. Therefore, transcriptional changes occurred and promoted the over-production of many important volatile compounds for the quality of white grapes
Hybrid injectable platforms for the in situ delivery of therapeutic ions from mesoporous glasses
Copper-containing bioactive glasses (Cu-MBGs) are attracting increasing interest as multifunctional agents for
hard and soft tissue healing due to the ability of released copper ions to stimulate osteogenesis as well as
angiogenesis and to impart anti-bacterial properties. The conjugation of these nanomaterials with a vehicle
phase based on thermosensitive hydrogels represents an effective strategy to design non-invasive injectable
devices for the in situ delivery of therapeutic ions from MBGs.
In this contribution, Cu-containing MBGs were prepared by an aerosol-assisted spray-drying method (MBG_Cu
2%_SD) in the form of microspheres (surface area of ca 220m2 g−1) and through a sol-gel synthesis (MBG_Cu 2%
_SG) in the form of spheroidal nanoparticles (surface area above 700m2 g−1). Both Cu-containing samples were
able to release copper ions, although with different rates and percentage release. MBG_Cu 2%_SG released the
total incorporated amount of Cu ions with a faster kinetics compared to MBG_Cu 2%_SD, that released approximately
the 60% of copper.
Cu-MBGs were incorporated with a final concentration of 20 mg/mL into a thermosensitive sol-gel system
consisting of a novel amphiphilic poly(ether urethane) based on a commercialy available Poloxamer 407 (P407),
with improved gelation ability, mechanical strength and stability in aqueous solution with respect to native
P407. Cu-MBG-loaded hydrogels were characterised in terms of sol-to-gel transition temperature and time, injectability
and stability in aqueous environment at 37 °C. The hybrid formulations showed fast gelation in
physiological conditions (1 mL underwent complete sol-to-gel transition within 3–5 min at 37 °C) and injectability
in a wide range of temperatures (5–37 °C) through different needles (inner diameter in the range
0.6–1.6 mm)
post hoc analysis of clarinet phase iii study to investigate the influence of diabetic status on progression free survival pfs of patients with neuroendocrine tumours nets treated with lanreotide lan or placebo pbo
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Evolution of the Phenolic Content and Extractability Indices During Ripening of Nebbiolo Grapes from the Piedmont Growing Areas over Six Consecutive Years
The phenolic composition and extractability indices of grape berries play a key role in assessing red wine quality because the relationship between grape phenolic maturity and wine phenolic composition is well known. In this work, grape quality indices were determined in Nebbiolo grapes from two growing areas of Langhe (South Piedmont), at different stages throughout the ripening process in six consecutive years (2004 to 2009), with the aim of evaluating the ripening- and growing area-related changes in the grape indices separately. The effect of vintage was also investigated. Ripeness data were compared with analogous data determined in Nebbiolo grapes grown in the Carema area (North Piedmont). The vintage effect far outweighed any changes in the grape indices introduced by the ripening stage, even those arising from differences in the production area. In the Langhe and Carema zones, the average berry mass, pH, total acidity, total anthocyanins extractable at pH 3.2, total flavonoids and non-anthocyanin flavonoids extractable at pH 1, and the seed maturity index were seasonally dependent. The more ripening-affected parameters were the technological ones. This work highlights the importance of determining the phenol extractability, since it provides relevant information that allows improved management of the maceration stage
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