Volatile characteristics of 50 peaches and nectarines evaluated by HP–SPME with GC–MS

Using HS–SPME–GC–MS, characteristics of the volatiles of 50 peaches and nectarines representing different germplasm origins were investigated. Ten of these peaches and nectarines were studied in two successive years. Eighty-four compounds were identified. Volatile composition was relatively consistent, but the amount of total volatiles and certain individual compounds varied between years. Moreover, the composition of volatiles and their contents depended on genotypic background and germplasm origin. Total volatiles in wild peaches and a Chinese local cultivar ‘Wutao’ were much higher than in the other groups. All the peaches and nectarines could be classified into four groups by principal component analysis of the volatiles (excluding C₆ compounds): ‘Ruipan 14’ and ‘Babygold 7’ with high contents of lactones, Chinese wild peaches and ‘Wutao’ with high contents of terpenoids and esters, seven cultivars with American or European origins with high content of linalool, and others without characteristic composition of volatiles.     

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.     

Changes in chemical constituents during the maturation and ripening of two commercially important pomegranate accessions

Pomegranate juice is well known for its health beneficial compounds. This study was undertaken to investigate changes in the major chemical composition in arils and peels during fruit maturation in two Israeli commercial accessions, ‘Wonderful’ and ‘Rosh-Hapered.’ In both accessions, the levels of total phenolic, antioxidant activity and hydrolysable tannins were reduced in the peels during maturation, while the anthocyanin level increased. The results show that the sugar content in the aril juice increased in both accessions while the levels of acidity and of citric acid decreased. However, these two accessions differed in other parameters in the aril juice, i.e., while the antioxidant and total phenolic contents significantly decreased in ‘Rosh-Hapered’, these changes were not observed in ‘Wonderful’. The anthocyanin level, however, increased in ‘Wonderful’ but did not change in ‘Rosh-Hapered.’ This knowledge could help establish the optimum harvest date ensuring the maximum nutritional properties of pomegranates.     

Waste waters from the leachate of mushroom as vine foliar treatments: influence on grape volatile composition over two consecutive seasons

Edible mushrooms production presents a potential problem for the environment, due to the large amount of waste generated. These wastes contain nitrogenous matter, which could be used as biostimulant in plants. The aim of this work was to study the effect of waste waters, from the mushroom production process, applied at veraison and 1 week later to grapevine leaves, on grape volatile compounds over two vintages. The results evidenced that mushroom water treatment decreased the grape content of certain terpenoids, C₁₃ norisoprenoids, benzenoid compounds and esters, increasing C6 compounds content during the first season. Treated mushroom water application slightly affected grape volatile composition. This was the treatment that least affected the content of grape volatile composition. Few differences were found after the biostimulation during the second vintage. The season was the dominant factor of grape volatile content variation compared to the treatment and their interaction.     

Comparison of major volatile compounds from Riesling and Cabernet Sauvignon grapes (Vitis vinifera L.) from fruitset to harvest

Background and Aims: Research on concentration changes of volatile compounds during grape physiological development has focused on the period from veraison to harvest. This study compared the developmental changes in the major volatile compounds released after the crushing of Riesling and Cabernet Sauvignon grapes sampled from fruitset to harvest during the 2007–2008 season. Methods and Results: Volatile compounds were extracted from the headspace of crushed Riesling and Cabernet Sauvignon grapes sampled throughout berry development using solid-phase microextraction and analysed by gas chromatography–mass spectrometry. A multivariate statistical approach coupled with analysis of variance was applied to compare the developmental changes in volatile compounds for the two cultivars. In both cultivars, E-2-hexenal was the most abundant volatile compound, and it showed a significant increase in concentration after veraison. Benzene derivatives discriminated ripe Cabernet Sauvignon grapes, whereas monoterpenes and sesquiterpenes discriminated both cultivars pre-veraison with a broader range of terpenes observed in the Cabernet Sauvignon samples compared with the Riesling samples. At veraison, terpene production in both varieties was low, but Riesling grapes produced some terpenes (geraniol and α-muurolene) post-veraison. Generally, esters and aldehydes were the major class of compounds from Riesling grapes, while Cabernet Sauvignon showed a greater tendency to form alcohols. Conclusions: Both Riesling and Cabernet Sauvignon grapes had a more complex volatile compound composition pre-veraison than post-veraison. This study suggests that some compounds that contribute to grape aroma may be produced pre-veraison, and not simply accumulate after veraison. Significance of the Study: Understanding the timing of volatile compound production and cultivar differences will guide viticulture researchers and growers in the optimisation of vineyard strategies to enhance grape aroma attributes that may, in turn, contribute to wine aroma.     

Discrimination of European wheat varieties using near infrared reflectance spectroscopy

Near infrared reflectance (NIR) spectroscopy combined with chemometrics was used to discriminate wheat varieties. A total of 249 samples of different wheat varieties from the 2003–2004 harvest were used to develop the best discriminant equation, by applying various scatters and mathematical treatments in the range of 400–2500 nm. Wheat varieties from Spain were ‘Sarina’, ‘Bolero’, ‘Berdún’, ‘Soisson’, ‘Chamorro’, ‘Artur Nick’, ‘Berdun’, ‘Marius’, ‘Anza’, ‘Kalifa’, and wheat varieties from France were ‘Galibier’ and ‘Quality’. The equation developed with the highest accuracy had an applied scatter of weighted multiplicative scatter correction, a math treatment of 2, 15, 8 (order of derivative, gap data points over which the derivative was taken, number of data points used in performing average smoothing). The percentage of correctly identified varieties was 99.5% for the calibration sample set and 94% for the validation sample set. The results demonstrated the usefulness of NIRS combined with chemometrics as a rapid method for discrimination of European wheat varieties. Although the application of the discriminant equation developed for the 2003–2004 harvest yielded a high rate, further test measurements are necessary to evaluate the robustness of the equation.     

Establishment of the volatile profile of ‘Bravo de Esmolfe’ apple variety and identification of varietal markers

The volatile composition of ‘Bravo de Esmolfe’ (BE) apple was achieved by headspace-solid phase microextraction (HS-SPME) followed by gas chromatography–mass spectrometry (GC–qMS) analysis using fruits from two different rootstocks (PAJAM2 and MM106), different trees of each rootstock, and different sections of each tree (north and south). Fruits were harvested in the maturity state defined for this variety and then stored for four months at 4 °C. During this period, analyses were made monthly. α-Farnesene was the compound found in the volatile profile of BE apple with the largest GC area. A large number of esters were also detected. Rootstocks, trees, and tree sections did not have statistical significance on the volatile composition of BE apples. However, the volatile composition changed throughout the storage period. The principal component analysis (PCA) allowed distinguishing between the apples obtained immediately after harvest and those stored for 4 months. In the first case, the volatile composition was related to the occurrence of aldehydes, aromatic hydrocarbons, and phenols and, in the second case, to esters and terpenoids. Ocymene, cymene, α-bergamotene, geranyl acetone, nerolidol, and ethyl 3-(methylthio)-propionate were identified for the first time in apples. This peculiar profile allows to propose them as varietal markers of BE apple variety. However, as this methodology has only been applied to BE apple, the occurrence of these compounds in other cultivars can not be excluded.     

“赤霞珠”葡萄转色后不同成熟度指标的变化

研究酿酒葡萄转色后不同成熟度指标的动态变化规律。以“赤霞珠”葡萄为试材,分别测定了技术成熟度和总酚成熟度指标,并进行了浆果感官评价。结果表明：转色后果实物理性状参数和糖含量迅速增加,转色后第4周达到最大值,成熟后期略有下降。果实中总花色苷含量逐渐增加,在转色后第6周达到最高,随后有所降低。浆果中可提取花色苷含量持续增加。细胞成熟指数、种子成熟指数和总酚指数总体上逐渐降低。果皮单宁含量变化较小,种子单宁含量在成熟前期显著降低（P＜0.05）,后期变化较小。不同分子大小聚合色素的含量逐渐增加,转色后第6周时达到最大值。浆果感官评价中各种成熟度的得分逐渐增加,果肉香气成熟度和果皮成熟度得分均在转色后第7周时最高,成熟后期变化较小。     

Aroma composition and sensory quality of fruit juices processed from cultivars of elderberry (<Emphasis Type="Italic">Sambucus nigra</Emphasis> L.)

The experiment included identification and quantification of 25 aroma compounds and determination of the sensory quality of fruit juices processed from 32 cultivars of black elder using enzymation. It was concluded that disappearance of 15 esters and the increases of four alcohols, six terpenoids, six carbonyls, six aldehydes, three ketones, eight alcohols, trans-rose oxide, nerol oxide, and dihydroedulan primarily might be due to enzymatic conversion of esters of fatty acids and enzymatic hydrolysis of glucosides as found by processing of juices from other fruits. Juices processed from the elderberry cultivars significantly differed with respect to aroma compound composition and sensory characteristics. Factor analysis of the combined data from measurement of aroma composition and sensory evaluation resulted in extraction of four factors with factor scores that could be used for selection of cultivars with different promising sensory properties and varying concentrations of phenolic acids and flavonoids that may be useful for processing of functional elderberry juices with health promoting properties.     

Investigation of bitterness in carrots (Daucus carota L.) based on quantitative chemical and sensory analyses

Bitterness is considered as an undesirable taste of carrots. Quantitative chemical analysis of potential bitter compounds of different carrot genotypes was combined with sensory analysis in order to identify key compounds likely to be responsible for the bitterness of carrots. Eight carrot genotypes (‘Bolero’, ‘Mello Yello’, ‘Nairobi’, ‘Tornado’, ‘Purple Haze’, ‘Line 1’, ‘Line 2’, and ‘Line 3’) representing extremes in sensory-perceived odour, flavour, and taste. Potential bitter compounds like polyacetylenes, isocoumarins and phenolic acids were quantified in the peel and the corresponding peeled carrot, and their contribution to bitterness in raw carrots was analysed by sensory profiling using multivariate data analysis. Falcarindiol and a di-caffeic acid derivative were highly related to bitterness in contrast to falcarinol and other potential bitter compounds. Falcarindiol and the di-caffeic acid derivative were primarily present in the peel whereas falcarinol was almost evenly distributed in the root. Investigation of bitterness revealed that high sugar content to some extent could mask the bitter perception of carrots. As falcarinol is the most bioactive of the carrot polyacetylenes the results of the present study indicate that there is a basis for improving the health effects of raw carrots without affecting sensory quality.     

Volatile constituents of palm wine and palm sap

Palm wine and pasteurised palm sap volatiles were collected, concentrated on a Tenax GC and analysed by gas chromatography and gas chromatography-mass spectrometry. Eighty-two components were identified: 47 esters, 9 alcohols, 5 acids, 6 carbonyls, 2 acetals, 4 terpenes and 9 hydrocarbons. These had all been found previously in conventional wines. Odour evaluation of the separated palm wine components as they eluted suggested that no one compound is responsible for the characteristic palm wine odour. The acetates of higher alcohols and the ethyl esters of straight-chain aliphatic C₆-C₁₀ acids seemed to be important and may play a big role in imparting the fruity nuances of characteristic palm wine odour. Their association with alcohols seemed also to be necessary for the expression of typical palm wine odour. The qualitative difference between palm sap aroma and palm wine aroma appeared to be due mainly to the presence of these esters and alcohols in palm wine and their apparent absence from palm sap, as well as to the presence of some low-boiling esters and alcohols in palm sap and their apparent absence from palm wine.     

Comparative study of primary and secondary metabolites in 11 cultivars of persimmon fruit (Diospyros kaki L.)

Primary metabolites (sugars, organic acids) and secondary metabolites (phenolics and carotenoids) were quantified by HPLC in fully ripe fruit of 11 kaki cultivars: ‘Amankaki’, ‘Cal Fuyu’, ‘Fuji’, ‘Hana Fuyu’, ‘Jiro’, ‘O’Gosho’, ‘Tenjin O’Gosho’, ‘Thiene’, ‘Tipo’, ‘Tone Wase’ and ‘Triumph’. Amongst the analysed cultivars, ‘Tone Wase’ stands out as the richest in sugars, particularly glucose, and cultivars ‘Tipo’ and ‘Triumph’ contained the highest amounts of organic acids. Cultivars ‘O’Gosho’, ‘Cal Fuyu’ and ‘Hana Fuyu’ contained the least sugars and cultivar ‘Jiro’ the least organic acids. Amongst the individual phenolic compounds catechin and gallic acid were present in highest concentrations. The predominant carotenoid in both skin and pulp of ripe persimmon fruit was β-carotene, the highest content was measured in skin of cultivar ‘Hana Fuyu’, which also contained the highest level of total carotenoids. In persimmon pulp, much lower values for carotenoids were obtained, particularly in fruit of cultivar ‘Cal Fuyu’.     

Volatile Compounds in Red Wines Processed on an Industrial Scale by Short Pre-fermentative Cold Maceration

Nero d’Avola and Shiraz grapes were subjected to pre-fermentative cold maceration at 4°C for about 24 h in industrial winemaking, in order to evaluate the effects of the pre-treatment on aroma profile. The volatile compounds were identified by gas chromatography-mass spectrometry and grouped into 14 chemical families 4 and 9 months after bottling. Principal components analysis (PCA) plots of the volatile compounds showed clear separation among wines from the Shiraz and Nero d’Avola varieties. For instance, Shiraz wines were characterized along the PC1 axe by esters of organic acids, norisoprenoids and C₆ alcohols, while Nero d’Avola wines were characterized by acetates and monoterpenic oxides and diols. Moreover, pre-treated samples showed significant (p?<?0.05) changes in volatile compounds belonging mainly to ethyl esters of straight chain fatty acids, acetates and norisoprenoids. The sensorial analysis showed that cold maceration contributed to development of a different aroma profile during bottle maturation if applied on Nero d’Avola or Shiraz variety.     

Improved loquat (Eriobotrya japonica Lindl.) cultivars: Variation of phenolics and antioxidative potential

Leaves and fruits (peel and flesh) of six improved cultivars (‘Mizuho’, ‘Néctar de Cristal’, ‘Mizauto’, ‘Mizumo’, ‘Centenária’ and ‘NE-3’) of loquat (Eriobotrya japonica Lindl.) were studied for their phenolic composition and antioxidant capacity. The analysis by HPLC-DAD-ESI-MS/MS allowed the identification of 18 compounds (8 hydroxycinnamic acid derivatives and 10 flavonoid glycosides). The quantification of the identified compounds revealed distinct profiles amongst the three analysed materials. Loquat leaves exhibited the lowest amounts of phenolics. 3- And 5-caffeoylquinic, and 5-feruloylquinic acids were the major compounds. Generally, ‘Mizauto’ cultivar presented the highest phenolic content. All loquat materials exhibited DDPH scavenging capacity, in a concentration-dependent manner, the leaves being the most active one. This effect seems to be related to the flavonoid content.     

Effects of cold storage on aroma compounds of white- and yellow-fleshed peaches

The stir bar sorptive extraction (SBSE) technique was used to determine volatile constituents in two peach cultivars, one yellow-fleshed (cv. Spring Lady) and one white-fleshed (cv. Regina Bianca). For both cultivars four distinct experimental samples were considered, each formed by fruits obtained with four different cultivation practices. In order to investigate the effects of cold storage on the volatile profile, on all peach experimental samples changes in aroma compounds after 1 and 2 weeks of storage at 1°C, plus 1 day at ambient temperature, were monitored; moreover, only on the four experimental samples from cv. Regina Bianca, the effect of a prestorage hot water treatment (46°C for 25 min) was also evaluated. On the isolate obtained by SBSE, 24 compounds were identified and quantified by GC-MS: saturated and unsaturated lactones, aldehydes, C₁₃ norisoprenoids, monoterpenes, alcohols and esters. The profile of the white-fleshed cultivar was characterised by a higher level of C₁₃ norisoprenoids, and, in particular, of 8,9-dehydrotheaspirone. In all experimental samples after 1 week of storage, plus 1 day at ambient temperature, a marked increase (on average by 89%) in total lactones was observed. This increase was due to a noticeable accumulation of saturated lactones with longer side chains (γ- and δ-decalactone) and unsaturated lactones ((Z)-dec-7-en-5-olide and γ-jasmolactone). Peaches analysed after 2 weeks of storage showed total lactone levels close to those detected in the samples at harvest, suggesting that increasing storage times reduced fruit ability to accumulate these character impact compounds of peach aroma. A similar effect of cold storage, although less marked, was also observed on C₁₃ norisoprenoid fraction, but only on cv. Regina Bianca. On the other hand, we did not find univocal effects of cold storage on C₆ aldehydes, whereas linalool, detected only in samples of cv. Spring Lady at harvest, disappeared quickly during the first days of storage. In samples of cv. Regina Bianca peaches subjected to hot water treatment, after 1 week of storage, lactone level was significantly reduced in comparison with untreated fruits, denoting a possible inhibition effect on lactone accumulation and on aroma development.     

Characterization of wax esters,free fatty alcohols and free fatty acids of crude wax from sunflower seed oil refineries

The sunflower seed wax (10–12%) from oil refineries was purified through two steps, namely, extraction using solvents and precipitation with chilled acetone. Fatty esters, free fatty alcohols and free fatty acids were separated by thin-layer chromatography (TLC). The fractions of fatty esters and free fatty alcohols were separated and identified by gas chromatography (GC) using a Dexil-300 column and OV-101 column, respectively, at temperatures from 150–290 °C and were further confirmed by Gas chromatography–mass spectrometry (GC–MS), using a capillary silica column SPB™-1 coated with polydimethyl siloxane. Among the long chain fatty esters (C₃₈–C₅₄), comprised of one unit of fatty alcohol and one unit of fatty acid through an ester linkage, the major esters were C₄₀–C_44, of which C₄₂ was predominant. These fatty esters, upon hydrolysis, followed by methylation and subsequent GC–MS analysis, showed the presence of C₁₆–C₃₀ fatty acids in the bound form, whereas methylation of native wax indicated the presence of C₁₈–C₃₀ fatty acids in the free form. Acetylation of hydrolysis product showed the presence of C₁₈–C₃₀ fatty alcohols in the bound form, where as acetylation of native wax indicated that the C₁₈–C₃₂ fatty alcohols were in the free form. n-Triacontanol (C₃₀), a plant growth regulator, was found in both free and bound forms.