Impact of cover crops in vineyard on the aroma compounds of Vitis vinifera L. cv Cabernet Sauvignon wine

This study compared the influence of different cover crops with clean tillage on wine aroma compounds of 5-year-old Cabernet Sauvignon vines. White clover, alfalfa, and tall fescue were used in the vineyard and compared with clean tillage. Aroma compounds of wine were analysed by solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC/MS). Forty-seven volatile compounds were identified and quantified. Wines made from grapes grown with various cover crops had higher levels of aroma compounds. Ethyl acetate, isoamyl acetate, ethyl octanoate, ethyl hexanoate, phenylethyl acetate, isoamyl alcohol, linalool, citronellol, β-damascenone, α-ionone, and 5-amyl-dihydro-2(3H)-furan were the impact odorants of sample wines. Wines from cover crop also had higher contents of these impact odorants than the control. For different cover crops, alfalfa sward yielded the highest levels, followed by the tall fescue treatment. According to the data analysis of aroma compounds and sensory assess, permanent cover crop may have the potential to improve wine quality.     

Effects of composition,storage time,geographic origin and oak type on the accumulation of some volatile oak compounds and ethylphenols in wines

The aim of this work was to study the effect of different parameters on the accumulation of volatile oak compounds and ethylphenols in red barrel-aged wines. For this, 510 wines, from four different geographic zones and aged for various times in different oak barrel types were analysed. The results of the statistical analysis showed that the compounds were in four groups, accounting for 82.99% of the variance. The enological parameters did not present correlation with any of these four groups. The wines that remained longer in oak barrels presented, in general, higher concentrations of the studied compounds. Three of the four geographic zones were similar to each other. The oak barrel type affected the value of the ratio cis/trans, but it did not affect the accumulation of any of the volatile oak compounds or ethylphenols.     

Determination of volatile compounds and quality parameters of traditional Istrian dry-cured ham

The aim of this work was to determine the characteristics of Istrian dry-cured ham by instrumental methods and sensory analysis. The aroma-active compounds of Istrian dry-cured ham from 2010 and 2012 were investigated by using headspace-solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics. 92 volatile aroma compounds of Istrian dry-cured ham were found. Volatile compounds belonged to several chemical groups: aldehydes (51.4; 51.3%), terpenes (16.5; 16.4%), alcohols (15.5; 13.2%), ketones (8.6; 7.4%), alkanes (3.8; 5.7%), esters (1.3; 1.6%), aromatic hydrocarbons (0.8; 3.9%) and acids (0.6; 0.9%). Principal component analysis (PCA) showed that fat content, tenderness and melting texture were positively correlated. Terpenes were strongly correlated with flavour of added spices. Sweet taste and the presence of esters were positively correlated as well as negative odour, raw meat flavour and water content.     

Changes in the aromatic composition of the Vitis vinifera grape Muscat Hamburg during ripening

A two-year study was carried out to determine the evolution of free and bound aromatic compounds of Muscat grape (sp. Vitis vinifera cv. Muscat Hamburg) during ripening. The most abundant free compounds detected were linalool, geraniol, citronellol, nerol, 3,7-dimethyl-1,5-octadien-3,7-diol (diendiol I) and 3,7-dimethyl-1,7-octadien-3,6-diol (diendiol II). In general, concentrations of the main free terpenols increased during grape development, except geraniol. In the glycosidically-bound fraction the major compounds were geraniol, linalool, citral, nerol, citronellol, α-terpineol, diendiol I, diendiol II, trans-furan linalool oxide (linaloloxide I), cis-furan linalool oxide (linaloloxide II), benzyl alcohol and 2-phenylethanol. At grape maturity, results showed a higher content of bound compounds than of free forms, with the exception of linalool, diendiol I, and diendiol II whose concentrations were greater in the free fraction, and limonene which was not detected in the bound fraction. On the basis Odour Activity Values, linalool was the most odour-active odorant. Other monoterpenes potentially contributing to Muscat aroma were rose oxide, citral, geraniol, nerol and citronellol.     

Effect of postharvest dehydration on the composition of pinot noir grapes (Vitis vinifera L.) and wine

This study was conducted in order to improve our understanding of how phenolics and aroma compounds change in wine grapes during postharvest dehydration. Pinot noir grapes grown in the Willamette Valley of Oregon were harvested at 22.0 and 24.0 °Brix. Grapes harvested at 22.0 °Brix were divided into three equal lots with one lot immediately used for wine production, and the remaining two lots placed inside an air tunnel with an air speed of 1.0–1.8 m s⁻¹, 38% relative humidity and a temperature of 22 °C. The soluble solids content and weight loss were measured daily and wines were made from grapes when they reached 24.8 and 26.7 °Brix. The soluble solids of grapes increased about 1 °Brix per day; therefore, on the third and fourth day the berries reached the desired concentration; weight loss was 14 and 16%, respectively. Results from berry phenolic analysis indicated that per berry anthocyanin amount remained unchanged during dehydration. The composition of proanthocyanidins isolated from berries changed during dehydration. Volatile compounds in wines made from dehydrated grapes contained more terpenes and norisoprenoids (β-ionone, β-damascenone) when compared to wine made from the original fruit. Wines made from increasingly dehydrated grapes tended to resemble the composition and flavour profile of wines made from grapes left on the vine (i.e. with extended ripening). The results of this study suggest that postharvest flavour changes consistent with changes during fruit ripening can occur in grapes when harvested early and allowed to dehydrate under controlled conditions prior to fermentation.     

Varietal and pre-fermentative volatiles during ripening of Vitis vinifera cv Nebbiolo berries from three growing areas

Flavour analysis of grape is a key step in quality evaluation. The Stir Bar Sorptive Extraction technique (SBSE, ‘Twister’®) was used to assess varietal and pre-fermentative volatile accumulation in ‘Nebbiolo’ berries, from véraison to harvest. Grapes were collected in three vineyards, representing different ‘crus’ in the cultivation areas of Barolo, Barbaresco and Roero (North–West Italy). Volatile constituents of grapes were identified and quantified by GC–MS.     

Phenolic compounds content and antioxidant activity in pomace from selected red grapes (Vitis vinifera L. and Vitis labrusca L.) widely produced in Brazil

The phenolic compounds content and antioxidant activity of pomace from the vinification of grape varieties widely produced in Brazil (Cabernet Sauvignon, Merlot, Bordeaux and Isabel) were investigated with a view to their exploitation as a potential source of natural antioxidants. Cabernet Sauvignon grape pomace was found to have the highest content of total phenolic compounds (74.75 mg gallic acid equivalent (GAE)/g), the highest antioxidant activity (determined using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods; 485.42 and 505.52 μMol Trolox equivalent antioxidant capacity (TEAC)/g, respectively), and the highest reducing power (determined using the FRAP method; 249.46 μMol TEAC/g). The Bordeaux variety showed the highest oxidation inhibition power (41.13%), determined using the β-carotene/linoleic acid method and the highest content of total anthocyanins (HPLC; 29.17 mg/g). Catechin was the most abundant non-anthocyanic compound identified in the grape pomace (150.16 mg/100 g) for all varieties. In this study, pomaces of the red wine vinification of Cabernet Sauvignon and Bordeaux varieties showed the highest potential as a source of antioxidant compounds and natural colourants, respectively.     

Residues of grape (Vitis vinifera L.) seed oil production as a valuable source of phenolic antioxidants

Phenolic compounds of seven grape seed samples originating from mechanical seed oil extraction were identified and quantified by HPLC–DAD before (intact seeds) and after (press residue) the oil recovery process. Total amounts of all identified compounds ranged from 4.81 (‘Cabernet Mitos’) to 19.12 g/kg (‘Schwarzriesling’) of defatted dry matter (DM; ‘Schwarzriesling’) for integral grape seeds, whereas their content in the press residues ranged from 2.80 (‘Cabernet Mitos’) to 13.76 g/kg of defatted DM (‘Spätburgunder’). This is the first study presenting comprehensive data on the contents of individual phenolic compounds comprising all polyphenolic subclasses of press residues from grape seed oil production also covering the determination of the antioxidant activities of each subclass (Folin–Ciocalteu, FRAP and TEAC assays). Additionally, the effects of different solvents on the yields of phenolic compounds were determined. Maximum yields were obtained using methanol/0.1% HCl (v:v), water [75 °C] and a mixture of ethanol and water [3:1; v:v], respectively, whereas pure ethanol resulted in poor polyphenol extraction. The results of the present study confirm the press residues of grape seed oil production still to be a rich source of polyphenolics with strong antioxidant activity.     

Analysis of volatile compounds in traditional smoke-cured bacon(CSCB) with different fiber coatings using SPME

The volatile compounds of Chinese traditional smoke-cured bacon (CSCB) were studied using SPMS-GC/MS. There were 48 volatile compounds identified and quantified, which belonged to several classes of chemical: 1 alkane, 16 aldehydes, 5 ketones, 9 alcohols, 4 thioethers and thiols, 3 furans and 10 phenols compounds. All the volatile compounds except for alkane was responsible for CSCB characteristic flavor. The major volatile compounds of CSCB came from smoking, oxidation and Maillard reaction, etc. Many volatile compounds were not reported in previous paper isolated by steam distillation method or nitrogen purge-and-steam distillation method on CSCB. It should be because of different method of isolating volatile substances from CSCB. Among the fibers tested, CAR/PDMS (carboxen/polydimethylsiloxane) fiber coating showed the highest area counts for most volatile compounds. CAR/PDMS coating extracted better those compounds whose linear retention indices (LRI) was lower than 926 (on average) and DVB/CAR/PDMS (divinylbenzene/carboxen/polydimethylsiloxane) those with higher LRI.     

Changes in physicochemical characteristics and volatile compounds of apricot (Prunus armeniaca L. cv. Bergeron) during storage and post-harvest maturation

The effects of storage and post-harvest maturation on the physicochemical characteristics and volatile constituents of Bergeron apricot were investigated during the 2007 season over two experiments. Fruits, harvested at two distinct stages of maturity, in two different experimental orchards, were stored in cold chambers at +1 °C for up to 3 weeks and then subjected to a post-harvest maturation in ripening chambers at 20 °C and 60–70% RH up to 7 days. Firmness, soluble solids (SS), titratable acidity (TA), and the levels of the main volatiles were determined. Physicochemical changes included a significant decrease of firmness during both storage and post-harvest maturation whereas the levels of SS and TA were found to be very similar. The results also indicated that, whatever their initial stage of maturity at harvest, the rates of softening of apricots during storage and/or post-harvest maturation were very comparable. During post-harvest maturation, the levels of C₆-compounds decreased drastically whereas, at the same time, those of esters, lactones and terpenic compounds greatly increased. During storage at 1 °C, a decrease of C₆-compounds was also observed. As regards other compounds, there were some statistically different results between samples but the changes observed for lactones, esters and terpenic compounds were relatively small in comparison to those observed during post-harvest maturation at 20 °C. The results also showed that, at the end, qualitative and quantitative differences can be observed in the “ready-to-eat” apricots according to their initial stage of maturity at harvest. On average, apricots harvested at the most advanced stage of maturity have, on average, the highest levels of soluble solids and the highest levels of volatile compounds of interest.     

Volatile profile of mango (Mangifera indica L.), as affected by osmotic dehydration

The effect of osmotic dehydration on the volatile fraction of mango fruit was studied. Osmotic treatments were carried out at atmospheric pressure (OD) and by applying a vacuum pulse (PVOD). Sucrose at 35, 45, 55 and 65 °Brix was used as osmotic solution until reaching 20 or 30 °Brix in the liquid phase of dehydrated mango. Volatile compounds of fresh and dehydrated samples were obtained by simultaneous distillation–extraction, and analyzed by GC–MS. In general, osmotic dehydration provoked changes in the concentration of analyzed compounds to different extents, depending on process conditions. The use of highly concentrated osmotic solutions, and the high level of sample osmodehydration, induced losses of volatiles with respect to the fresh samples. On the other hand, more heavily diluted solutions and shorter treatment times (lower osmodehydration level) could give rise to the enhancement of volatile production. In these cases, sample mass loss was reduced during treatment since sugar gain was promoted against water loss.     

Chemical composition and antioxidant capacity of free volatile aglycones from basil (Ocimum basilicum L.) compared with its essential oil

The present paper examines the chemical composition and antioxidant capacity of free volatile aglycones from basil compared to their essential oil. The comparison of chemical composition of volatile aglycones with the chemical composition of essential oil reveals four common compounds: eugenol, chavicol, linalool and α-terpineol. For the evaluation of the mentioned antioxidant capacities, two different methods were performed: the 2,2′-diphenyl-1-picrylhydrazyl radical scavenging method (DPPH) and ferric reducing/antioxidant power assay (FRAP). DPPH method shows that free volatile aglycones possess good antioxidant properties comparable with that of the essential oil and well-known antioxidant butylated hydroxytoluene (BHT), but less than pure eugenol. The results obtained by FRAP method show that these compounds are some less effective antioxidants than essential oil and BHT.     

The components of cuttlefish (Sepiella maindroni de Rochebruns) oil

The oil extracted from the viscera of cuttlefish (Sepiella maindroni de Rochebruns) was studied. Fatty acid composition, cholesterol content and volatile compounds composition were analysed. The composition of fatty acids was monounsaturated fatty acids, 50%, followed by polyunsaturated fatty acids, 31%, and finally saturated fatty acids, 19%. The total cholesterol was 1.39 mg/100 g oil. Hexanal, (E,E)-2,4-heptadienal, 2-nonanone, benzothiazole, 2-methyl-4-propylthiazole, 2,3-butanediol, 1-penten-3-ol and ethyl oleate were considered as principal contributors to the distinctive odour of cuttlefish oil.     

Changes of volatile compounds in wine vinegars during their elaboration in barrels made from different woods

Changes in the volatile components of red wine vinegars and balsamic vinegars were investigated during 1 year of aging in wood barrels and bottles. Barrels of four different woods (oak, chestnut, acacia and cherry) were used. A total of 57 volatile compounds were analysed by Gas Chromatography–Flame Ionization Detection (GC–FID) and Headspace Sorptive Extraction GC–Mass Spectrometry (HSSE-TD–GC–MS). We observed significant increases in the total content of volatile compounds only for balsamic vinegars. The concentrations of ethyl furoate, ethyl benzoate, benzaldehyde and acetophenone were highest in cherry barrels. These compounds, then, seem to be characteristic of this wood. Oak lactones presented the highest increases for vinegars aged in oak. Eugenol was only present in vinegars aged in chestnut and oak barrels. Oak and cherry seem to be the best type of wood for aging of vinegar due to their distinctive aromatic characteristics.     

Contribution of free and glycosidically-bound volatile compounds to the aroma of muscat “a petit grains” wines and effect of skin contact

Free and glycosidically-bound volatile compounds of must, skin and wine from Muscat “a petit grains” cultivated in Spain were determined, and the effect of different skin contact times on the aroma composition and sensory characteristics of wines was investigated. Must and wine had a large quantity of mono-terpenes, mainly linalool, geraniol, and nerol. The most abundant glycosylated fraction was the mono and poly-oxygenated terpenes, followed by benzene compounds and norisoprenoids. Must skin contact at 18 °C during 15 and 23 h produced an important increase in the free and bound varietal compounds, which suggests the use of glycosidic enzymes, together with skin maceration, to increase wine aroma. From a sensory standpoint, must skin contact was very positive, since it brought about an increase in the fresh and fruity characteristic of the wines, and they also had more body.     

Antioxidant activity and phenolic content of 16 raisin grape (Vitis vinifera L.) cultivars and selections

Six raisin grape cultivars and 10 new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze–dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 μmol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin–Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 μg/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 μg/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5–209.1 μg/g DW) and epicatechin (126.5–365.7 μg/g DW) than the other samples.     

Volatile compounds of copoazú (Theobroma grandiflorum Schumann) fruit

Volatile compounds were isolated from copoazú (Theobroma grandiflorum Schumann) fruit by liquid–liquid extraction at two different pH values of 3.3 (natural) and 7. The volatile extracts were analyzed by capillary GC–FID and GC–MS. Among the 56 compounds identified at two pH values, many of them were only present in the lower pH extract, confirming the presence of bound compounds in copoazú. Ethyl butanoate, ethyl hexanoate and linalool were the major constituents found in copoazú fruit.     

Analysis of free and glycosidically bound compounds of ash gourd (Benincasa hispida): Identification of key odorants

Free and glycosidically bound aroma compounds of ash gourd were investigated. Gas chromatography–mass spectrometry (GC/MS) analysis of the free aroma compounds isolated by both steam distillation and high vacuum distillation revealed the presence of acetoin as the major constituent in both the oils. Acetoin was also identified as the major constituent existing as glycosidic conjugate. GC–olfactometry (GC–O) of the volatile oil based on detection frequency (olfactometry global analysis) was further used to characterise odour active compounds of the vegetable. Based on odour activity value (OAV) measurements the potent odorant among these were identified as acetoin (9522.5), octanal (8571) and nonanal (24,000). The region corresponding to the characteristic ash gourd aroma when collected by cryotrapping from a packed GC column and subsequently analysed by GC/MS was found to be mainly comprising of acetoin suggesting the role of this compound as the key odour active compound of this vegetable.     

Bound aroma compounds of Gual and Listán blanco grape varieties and their influence in the elaborated wines

Listán blanco and Gual are two white grape varieties grown in Spain (Canary Islands) and Gual is also grown in Portugal (Madeira Island). Wine quality could be improved by exploiting the varietal characteristics present in grapes as aroma precursors. At the present time, the enologic potential of these varieties has not yet been studied. Aroma precursors in musts and skins, and free volatiles in wines were determined in samples of both varieties. Aroma precursors of must and skins were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by gas chromatography-mass spectrometry (GC–MS). Among the aroma precursors analysed, only α-terpineol, linalool and linalool oxides, 4-allyl-2,6-dimethoxyphenol, 2-methoxy-4-vinylphenol, 4-hydroxybenzaldehyde, vanillin and benzyl alcohol showed contents in grapes comparable to the levels observed in wine volatile compounds.