1,720,995 research outputs found
EPR evaluation of the antiradical activity of wines containing high concentrations of resveratrol
No full textThe ability of two samples of red wine with different resveratrol concentrations to inhibit hydroxyl radicals (·OH) produced by a Fenton-type reaction was assessed using the method of electronic paramagnetic resonance (EPR). One sample was an autochthonous wine, Uvalino, which has a very high resveratrol concentration; the second was another red wine with a much lower resveratrol concentration. The ability of the sample of Uvalino wine to obstruct hydroxyl radicals was evident, but it wasn't much better than the ability of the sample of wine with a lower resveratrol concentration. The resveratrol concentration of wine is an important factor for the inhibition of the formation of free radicals, especially hydroxyl radicals; however, it is not the only one responsible for this properly of wine. Resveratrol concentration can act synergically with other factors, such as polyphenols, which are also contained in wine and have antioxidant properties
Evaluation of fruit aroma quality : comparison between gas chromatography-olfactometry (GC-O) and odour activity value (OAV) aroma patterns of strawberries
No full textGas chromatography-olfactometry (GC-O) is based on the use of human assessors as a sensitive and selective detector to ascertain odour-active volatile compounds in a sample extract, whereas odour intensity value (OAV) determination is widely used to obtain odour patterns starting from quantitative compositions. Whether there is an exact parallelism between odour patterns obtained from GC-O parameters and OAV is not yet well investigated. To this aim, the OAV and GC-O odour patterns of six strawberry genotypes were compared. Esters represented 97.9-99.8% of total volatiles, with methyl butanoate being the main Compound; dimethyl disulfide, dimethyl trisulfide, gamma-heptalactone and delta-decalactone were detected only by GC-O. OAV indicated that 25 volatiles out of 39 could actually contribute to the odour pattern, while the GC-O sensory panel perceived 30 odorous events. The major odour contributors in OAV and the maximum odour intensities of odour events in GC-O were genotype dependent. Comparing OAV with GC-O patterns, the spatial relationships in principal component analysis biplots were comparable: 'VR4' was opposed to 'Alba' and 'CS4', and 'Dora' to 'Darselect' and 'Eva'. GC-O and OAV resulted in comparable strawberry odour patterns, GC-O giving the most detailed qualitative and quantitative description. However, being GC-O, a time-consuming method, it should not be routinely used
Influence of drying techniques and growing location on the chemical composition of sweet pepper (Capsicum annuum L., var. Senise)
No full textThe aim of this work was the comprehensive characterization of dried Senise pepper, a tasty landrace, to verify the suitability of common industrial processing and different growing locations to its production. Fruits from experimental CREA fields of Battipaglia (southern Italy) and Montanaso (northern Italy), dried using a solar dryer or a forced air oven, were compared with lyophilized and commercial samples. Solar dried samples showed a retention of glucose, while fructose levels decreased. Citric acid was the main acid in all samples, showing a differentiated behavior upon processing, with higher content in Battipaglia samples. The ascorbic acid showed the highest correlation with antioxidant assays, and both drying methods decreased its content, with better retention in Battipaglia samples. Drying did not markedly affect carotenoid levels, showing higher content in Battipaglia peppers. Both drying technique and mostly growing location influenced the volatile profile, with higher apocarotenoid content in Battipaglia samples.
Practical applications
The use of Senise red pepper, a tasty landrace awarded in 1996 with the PGI certification mark, is spreading even outside Italy due to the renewed interest for high quality products with excellent taste and healthy properties. These peppers are mostly sun‐dried following a traditional procedure and consumed as spice. New approaches regarding the type of drying and the growing location of this spice, together with the knowledge about the changes in quality indexes with processing, can be useful for a better exploitation of this product, increasing its market availability and lowering the cost of production
Changes of pectic composition of “Annurca” apple fruit after storage
No full text'Annurca' apple fruit, which is commonly cultivated in Southern Italy and undergoes, after harvest, a typical reddening treatment to turn the apples' skin red, is noticeable for its high firmness. An 'Annurca' variety, called 'Bella del Sud' is examined for its pectic composition after reddening and just after cold storage. Pectins, extracted with water and potassium oxalate, change their composition after different storage regimes with respect to unstored fruit. 'Annurca' pectin, as analyzed by gel-permeation chromatography, is composed of three types of polymers (high MW, >350 kDa, medium MW 350-110 kDa, low MW 40-9 kDa). Gel-permeation chromatograms revealed that the medium MW polymers decreased after normal atmosphere storage. Eluates were subjected to enzymatic and chemical hydrolysis, then to HPLC analysis. The high and medium MW polysaccharides were rich in galacturonic acid. Low MW were rich in neutral sugars. The storage-induced differences in sugar composition revealed that the most important changes are loss of galacturonic acid in medium MW fragments, increase of glucose, rhamnose and arabinose and depletion of mannose-galactose units in low MW fragments
Partial removal of water before freezing: Cultivar and pre treatments as quality factors of frozen muskmelon (Cucumis melo, cv reticulatus Naud).
No full textThe infuence of both the cultivar and the dehydration method, applied before freezing, on quality characteristics of dehydro-frozen muskmelon spheres has been studied. Water was removed from muskmelon cultivar Mirado and Rony, prior to freezing, by Dewatering-Impregnation-Soaking in concentrated solution (DIS) for 1 h, air dehydration and combined DIS-air dehydration to a fnal 50% weight reduction. The results of the analysis of exudate loss, texture, colour, aroma composition and sensory charac¬teristics ascertained the crucial importance of the cultivar which had a great infuence on the quality of the end products. Moisture reduction prior to freezing reduced exudate loss and improved texture at thawing. All the pre-treatments caused the loss of ethyl esters, namely ""positive"" aroma compounds, while the alcohols, ""negative"" aroma compounds, increased in air dehydrated fruits and remained stable in the DIS-treated ones. This fnding could explain the higher sensory acceptability of the DIS-treated fruit when compared with those pre-air dehydrate
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