Monoterpenic characterization of white cultivars from Vinhos Verdes appellation of origin (North Portugal)

The monoterpenic composition of Alvarinho, Arinto, Avesso, Azal, Batoca, Loureiro and Trajadura Vitis vinifera cultivars from the Vinhos Verdes region (Portugal), in respect to free volatile compounds as well as glycosidically bound aroma precursors, was determined by GC-MS after adsorption on XAD-2 resin. Eighteen monoterpenic compounds were identified and quantified in the free form and twenty-two compounds in the glycosidically bound form. In the free fraction, the Loureiro variety could be easily differentiated from the other six varieties by the important levels of linalool, above the odor perception threshold. This was in contrast to Alvarinho, Avesso, Arinto, Aza and Trajadura, where geraniol prevailed. The Batoca variety showed a very poor monoterpenic profile in the free form. On the other hand, Alvarinho was the richest variety in respect to the glycosidically bound form, followed by Loureiro. In this fraction, linalool and 3,7-dimethylocta-1,5-dien-3,7-diol were the most abundant compounds in the Loureiro grape cultivar; additionally, the isomer (E)-8-hydroxylinalool was in a higher concentration than (Z)-8-hydroxylinalool (sub-region of Sousa),while for the rest of the varieties the (Z) isomer prevailed.The authors thank the Comissao de Viticultura da Regiao dos Vinhos Verdes - EVAG. Divisao de Vitivinicultura e Fruticultura da Direccao Regional de Agricultura de Entre Douro e Minho - DVF-DRAEDM for providing the grape samples for this study. Thanks to Dr. Vilanova (Mision Biologica de Galicia - CSIC, Spain) and Dr. Solange I. Mussatto (University of Minho) for their help in the revision of the manuscript

Volatile and glycosidically bound composition of Loureiro and Alvarinho wines

Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, respecting free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by GC-MS after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, respecting varietal compounds, Loureiro wines are richer than Alvarinho ones with regard to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrate that wines of both varieties may benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, α-terpineol, contributing with fruity and floral notes, and β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agree with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.Centre of Biological Engineering of Universidade do Minho; Estação Vitivinícola Amândio Galhano (EVAG); Solar de Serrade; EVAG; Comissão de Viticultura da Região dos Vinhos Verdes

Study of the volatile and glycosidically bound compounds of minority Vitis vinifera red cultivars from NW Spain

Aroma composition was analyzed in grape musts from five Vitis vinifera red cultivars (Pedral, Sousón, Caíño Redondo, Espadeiro and Mencía) grown in Galicia (NW Spain) with the aim to know the potential profile of these varieties. All cultivars were collected from Coto Redondo Winery vineyard (A.O.C. Rías Baixas) and grown under the same conditions. All cultivars (with a total of 96 aroma compounds, 35 free volatile and 61 glycosidically bound compounds) were identified and quantified by GC-MS. The results showed that Caíño Redondo and Pedral had the highest concentrations of volatile compounds. The free fraction showed the highest concentration for all cultivars studied with the exception of Pedral. High concentrations of free C6-compounds and free alcohols were found for all red cultivars studied, especially for Caíño Redondo. Sousón and Mencía presented similar characteristics in the free fraction. Pedral showed an important contribution of glycosidically bound compounds. This cultivar showed the highest concentration of bound alcohols, terpenoids, volatile phenols, and C13-norisoprenoids. With terpenoids, higher levels were found in the bound fraction than in the free fraction. Regarding C13-norisoprenoids, Pedral also showed an important contribution of these varietal compounds. The principal component analysis (PCA) showed a good separation of the different grape cultivars, so they could be discriminated based on their potential volatile composition. The oenological potential of ancient and minority grape varieties from NW Spain, with the aim to provide genetic diversity, is illustrated with this work.This work was partially supported by the project 07MRU016403PR from the Galician government (Spain). The authors would like to thank to the Coto Redondo Winery from As Neves - Pontevedra (Galicia, Spain) especially Antonio Mendez. P. Canosa and M. Vilanova are grateful to the Spanish Ministry of Education and Conselleria de Innovacion e Industria from Xunta de Galicia for different financial programs

Composition of Sulla (Hedysarum coronarium L.) honey solvent extractives determined by GC/MS: norisoprenoids and other volatile organic compounds

Samples of unifloral sulla (Hedysarum coronarum L.) honey from Sardinia (Italy) were analysed. To investigate the chemical composition of the honey volatiles two solvent systems were used for ultrasonic solvent extraction (USE): 1) a 1:2 (v/v) pentane and diethyl ether mixture and 2) dichloromethane. All the extracts were analysed by GC and GC/MS. These procedures have permitted the identification of 56 compounds that include norisoprenoids, benzene derivatives, aliphatic compounds and Maillard reaction products. Norisoprenoids were the major compounds in both extracts, dominated by vomifoliol (5.3-11.2%; 9.6-14.0%) followed by minor percentages of other norisoprenoids such as α-isophorone, 4-ketoisophorone, 3-oxo-α-ionol or 3-oxo-α-ionone. Other abundant single compounds in the extracts were 3-hydroxy-4-phenylbutan-2-one (0.8-5.4%; 0.6-5.7%) and methyl syringate (3.0-5.7%; 2.2-4.1%). The composition of the volatiles and semi-volatiles in the obtained extracts suggests that sulla honey is quite distinctive relative to the other honeys that have been chemically studied by GC/MS, but no specific markers of the honey botanical origin were foun

An unbiased approach elucidates variation in (S)-(+)-linalool, a context-specific mediator of a tri-trophic interaction in wild tobacco

Plant volatile organic compounds (VOCs) mediate many interactions, and the function of common VOCs is especially likely to depend on ecological context. We used a genetic mapping population of wild tobacco, Nicotiana attenuata, originating from a cross of 2 natural accessions from Arizona and Utah, separated by the Grand Canyon, to dissect genetic variation controlling VOCs. Herbivory-induced leaf terpenoid emissions varied substantially, while green leaf volatile emissions were similar. In a field experiment, only emissions of linalool, a common VOC, correlated significantly with predation of the herbivore Manduca sexta by native predators. Using quantitative trait locus mapping and genome mining,we identified an (S)-(+)-linalool synthase (NaLIS). Genome resequencing, gene cloning, and activity assays revealed that the presence/absence of a 766-bp sequence in NaLIS underlies the variation of linalool emissions in 26 natural accessions. We manipulated linalool emissions and composition by ectopically expressing linalool synthases for both enantiomers, (S)-(+)- and (R)-(−)-linalool, reported to oppositely affect M. sexta oviposition, in the Arizona and Utah accessions.We used these lines to test ovipositingmoths in increasingly complex environments. The enantiomers had opposite effects on oviposition preference, but themagnitude of the effect depended strongly both on plant genetic background, and complexity of the bioassay environment. Our study reveals that the emission of linalool, a common VOC, differs by orders-of-magnitude among geographically interspersed conspecific plants due to allelic variation in a linalool synthase, and that the response of a specialist herbivore to linalool depends on enantiomer, plant genotype, and environmental complexity

Characterization and differentiation of five “vinhos verdes” grape varieties on the basis of monoterpenic compounds

The aromatic profiles of three white grape varieties (Alvarinho, Loureiro, and Avesso) and two red varieties (Amaral and Vinhão) from the Vinhos Verdes region have been established with respect to the monoterpenic compounds, present either in free and in glycosidically bound fractions. Seventeen compounds have been identified and quantified in the free form and 21 in the glycosidically bound form. Loureiro variety is characterized by important levels of linalool in the free fraction, above the odour perception threshold; in contrast, Alvarinho and Avesso varieties do not contain compounds above the perception threshold. For Alvarinho, geraniol prevails, followed by linalool, while Avesso only has, in much low concentration, geraniol, nerol and citronellol; red varieties do not contain terpenic compounds. Loureiro and Alvarinho are still the richer varieties with regard to the glycosylated fraction; linalool and 3,7-dimethylocta-1,5-dien-3,7-diol have equivalent concentrations, and linalool is around the odour perception threshold; Avesso does not contain linalool. The isomers (Z) and (E) of 8-hydroxylinalool seem to differentiate white varieties; they are similar in Loureiro but the (Z) isomer prevails in Avesso and especially in Alvarinho; Avesso has a more balanced distribution. Amaral only contains α-terpineol, nevertheless of similar concentrator found in Loureiro; Vinhão has a more balanced distribution of isomers but the concentrations are very low. The results show that profiles of the terpenic compounds vary to a significant degree for the grape varieties studied and as is already known empirically, the white varieties are richer than red varieties, especially Loureiro.União Europeia - Fundo Social Europeu (FSE) - Programa Operacional Agricultura e Desenvolvimento Rural (PO AGRO) - Project no. 202

Glycosidic aroma compounds of some portuguese grape cultivars

Determinação dos compostos glycosidicos do aroma de uvas poruguesa

Aroma components of Galician Albariño, Loureira and Godello wines

Wines of the three most interesting Galician white grape varieties have been deeply analyzed for three aroma categories: the volatile compounds, except for monoterpenols, the monoterpenols and the bound forms. Many compounds showed significant differences between the wine groups, as proved by Tukey's test, e.g. for methanol, trans and cis 3-hexen-1-ols and relevant ratio, benzaldehyde and 4-vinylguaiacol in the first category, and for the most part of compounds of the other two categories. Loureira and most Albariño wines contain linalool and ho-trienol at a level of sensorial contribution. The relevant average terpene profiles show many similarities, especially for Albariño and particularly if considering the contents and relevant ratios of furan and pyran linalool oxide isomers, of ho-diendiols I and II and of geraniol. On the other hand differences could be stated for some compounds, mostly under the bound forms. Godello wines, with the poorest content of monoterpenols under both forms, are principally characterized by a marked level of bound benzaldehyde, with contemporary presence of a considerable average level of the free form. PCA data treatments on both monoterpenols and aglycons from the bound forms, showed a good separation among the groups as well a good homogeneity and varietal correspondence of the wines