Varietal Origin Research Articles

Volatile Profile Characterization of Extra Virgin Olive Oils from Argentina by HS-SPME/GC-MS and Multivariate Pattern Recognition Tools

The distinctive aroma of virgin olive oil is attributed to a large number of chemical compounds of different classes such as aldehydes, alcohols, esters, hydrocarbons, ketones, furans, and other volatile compounds that are not yet identified. The aim of the present study lies in the characterization of compound volatile profile of the most representative olive oil cultivars produced in Argentina. The methodology proposed was based on the development of headspace (HS)-SPME/GC-MS with the subsequent analysis of the chemical fingerprints using a discriminant analysis method and a principal component analysis data compression strategy to distinguish olive oils from different varietal origins. Carboxen/polydimethylsiloxane (75 μm) fiber was the most efficient to trap volatile compounds. Optimization of the SPME conditions was also carried out using multivariate methods. To avoid the influence of factors other than the cultivar, olive trees were cultivated under the same agronomic and pedoclimatic conditions; olive fruits were picked at the same stage of ripeness, and their oils were extracted with the same processing system. Volatile fractions from oils of the analyzed cultivars consisted of a complex mixture of more than 40 compounds. Both quantitative and qualitative differences were found among cultivars. The analytical data association with multivariate analysis constitutes a reliable analytical tool with potential ability to discriminate monovarietal extra virgin olive oil from Argentina.

Artificial vision and chemometrics analyses of olive stones for varietal identification of five French cultivars

Visual and metric examinations of the agricultural products like olive stones to determine the varietal origin requires specialists who cannot always conclude with certainty because of the large number of varieties identified. This study aims to overcome the traditional observations of the olive stone by replacing it with an artificial vision and chemometric treatment. The potential of this approach is shown by applying it to the varietal identification of olive stones from five main French cultivars. Two hundred and six variables are extracted from two stone pictures (front and profile). A Principal Component Analysis (PCA) allows projection of the five stone groups corresponding to the five cultivars. Partial least square-discriminant analysis (PLS-DA) regression predicts the varietal origin of the stones. The best model considers all the data of front and profile pictures and gives 100% of correct classification. The methodology can be proposed as an alternative method for the recognition of olive fruits from five main French cultivars and can be extended to the varietal identification of stone fruits.

Characterization of Novel Single-Variety Oxygenated Sesquiterpenoid Hop Oil Fractions via Headspace Solid-Phase Microextraction and Gas Chromatography–Mass Spectrometry/Olfactometry

The volatile composition of novel varietal oxygenated sesquiterpenoid hop oil fractions ("spicy essences") was characterized by headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry. Oxygenated sesquiterpenes represent the major chemical compound class, accounting for at least 65% of the total volatile fraction. In addition to oxygenated sesquiterpenes, spicy hop essences consist of several ketones, sesquiterpene and monoterpene hydrocarbons, and a relatively high number of unidentified compounds. On the basis of their relative composition, spicy hop essences can be fully differentiated according to their varietal origin. Multidimensional gas chromatography in combination with time-of-flight mass spectrometry on spicy hop essence cv. Spalter Select further demonstrated the enormous complexity of this particular hop oil fraction. The aromagram obtained via gas chromatography-olfactometry comprised nine odor-active regions described in terms of "citrus", "green", "haylike", "earthy", "woody", and "spicy". 2-Undecanone, 2-tridecanone, γ-cadinene, α-calacorene, calarene, humuladienone, caryolan-1-ol, caryophyllene oxide enantiomers, and humulene epoxide II are tentatively identified in the odor-active zones.

Chemometric Classification of Potatoes with Protected Designation of Origin According to Their Producing Area and Variety

Potatoes from Galicia (northwestern Spain) are subjected to a Protected Geographic Indication (PGI) according to European legislation. Ten trace elements (Li, Na, K, Rb, Ca, Fe, Mg, Mn, Cu, and Zn) have been determined by atomic spectrometry in two sets of potato samples: Geo-Origin.set and Variety.set. The first data set is composed of samples of the only variety authorized by PGI (Kennebec) with two geographical origins: Galician and non-Galician. The second set corresponds to samples from different varieties but with only Galician geographical origin. Chemometric pattern recognition techniques have been applied to the study of potato geographical and varietal origins in relation to their capability for translocating metals from soil to tuber. Also, authentication models for classifying potato samples with Galician PGI based on metal fingerprints have been developed. The results obtained showed that samples of the same variety, Kennebec, have different metal fingerprints when they have been produced in different geographic locations. Also, diverse potato varieties cultivated on equal geographic Galician origin presented different metal profiles as well. Therefore, it can be concluded that classification studies on the differentiation of geographical origin of foods should take into account information of production area together with varietal data. Otherwise, classification obtained on the basis of the geographical origin could be due to the different variety or vice versa. Finally, two models were constructed for Kennebec Galician samples against Kennebec from other origins as well as against other varieties cultivated in Galicia (Liseta and Baraka). Both models achieved adequate classification rates (93-100%), good sensitivities, and total specificities (100%), allowing the fraud detection in the PGI label.

Varietal differentiation of white wines on the basis of phenolic compounds profile

The authenticity of grapevine varieties is a very important topic in the Czech Republic, where varietal wines is very important for wine drinkers. The wines from 7 grapevine varieties were investigated. Sixteen phenolic compounds belonging among hydroxybenzoic and hydroxycinnamic acids, stilbenes, and flavan-3-ols were analysed by HPLC method. The aim of this study was to find markers of varietal origin of wines among the phenolic compounds studied. The analytical parameters obtained were evaluated for this purpose by CVA (canonical varietal analysis) method. It proved to be successful in detecting the following grapevine variety authenticity markers: hydroxycinnamic acids (i.e. p-coutaric acid and caftaric acid), hydroxybenzoic acids (protocatechuic acid and syringic acid), and flavan-3-ols <br />((–)-epicatechin and (+)-catechin).  

Biochemical Evaluation of Triploid Progenies of Diploid × Tetraploid Breeding Populations of Camellia for Genotypes Rich in Catechin and Caffeine

To verify the quality of triploid varieties of Camellia tea species at the secondary metabolite level, we tested caffeine and catechin profiles of 97 F(1) segregating progenies in two breeding populations with a common tetraploid parent and diploid parents of two geographic and varietal origins. Catechin and caffeine levels of the triploid progenies were quantified and compared against their diploid parent. Some of the progenies showed better performance than their diploid parent. Most of the progenies of the diploid C. sinensis × tetraploid cross showed heterosis for caffeine and EGCG. Progenies of the C. assamica subsp. lasiocalyx × tetraploid cross showed heterosis for +C, EC, EGC, and TC. The genomic contributions of the diploid parent seem to be the main factor in the variation between the two populations. Our studies showed quantitative enhancement of some of the quality-related parameters in tea, providing a platform to refocus on this classical breeding approach for developing quality cultivars in tea.

Characterisation of pear distillates from wild and cultivated varieties in Sardinia

SummaryThe aroma fraction of Italian distillates of wild (Pyrus amygidaliformis, Vill., namely ‘Pirastru’) and cultivated (Pyrus communis, L. cvs. ‘Coscia’, ‘Precoce di Fiorano’ and ‘Butirru de Austu’) pear varieties grown in the northern part of the island of Sardinia was investigated. Distillates from fermented mashes were obtained from the same producer and, in most cases, for 3 years following the same production process. Aroma analyses were performed by GC‐FID and GC‐MS techniques with direct GC injection of full proof distillates. Differences were found in the aromatic profile of all the distillates depending on their varietal origin. Wild Pirastru pear distillates were the richest in isoeugenol (0.186 g hL−1 a.a.), ethyl benzoate (0.388 g hL−1 a.a.) and ethyl phenylacetate (0.12 g hL−1 a.a.) but the poorest in 1‐hexanol (2.69 g hL−1 a.a.), n‐hexyl acetate (0.07 g hL−1 a.a.), Σ‐farnesene isomers (0.80 g hL−1 a.a.) and citronellol (0.007 g hL−1 a.a.). Pirastru distillates were also the poorest in methyl and ethyl unsaturated decanoate isomers, the so‐called Williams pear esters (0.002 g hL−1 a.a.). On the contrary, these compounds that characterise the aroma of Williams pear distillates were abundant in Coscia spirits (1.032 g hL−1 a.a.). The latter, together with Precoce di Fiorano, were rich in farnesene isomers (6.48 and 9.26 g hL−1 a.a. respectively). Evaluation of the data by univariate (anova and Kruskal–Wallis) and multivariate (PCA and HCA) statistical analyses revealed that some components (the classes of acetates, farnesene isomers, methyl and ethyl unsaturated decanoate esters and citronellol) are relevant in discriminating the distillates according to variety.

Biological and genetic characterisation of Phoma macrostoma isolates with bioherbicidal activity

The fungus Phoma macrostoma Mont. isolate 94-44B was registered as a bioherbicide for control of broadleaved weeds in Canada and the USA in 2011 and 2012, respectively. To obtain the registrations, the fungus had to be characterised both biologically and genetically. The objectives of this study were to demonstrate that bioherbicidal activity was associated with specific genetic markers and to determine whether bioherbicidal activity was a general trait of the species or only selected isolates. A collection of 64 isolates of P. macrostoma was established. A greenhouse bioassay and bioherbicidal-specific primers were used to determine bioherbicidal activity of all isolates. Only isolates originating from Canada thistle demonstrated the ability to reduce dandelion seedlings and display the 853 bp amplicon for the bioherbicidal-specific primer. Bioherbicidal isolates were consistently differentiated from all other isolates with two main genotypic groupings (I and II) arising from internal transcribed spacer (ITS) and amplified fragment length polymorphisms (AFLP) sequence analyses. Using AFLP, two biotypes of bioherbicidal isolates were also differentiated by the presence or absence of an AFLP marker at a single polymorphic locus. The genetic divergence among the bioherbicidal and nonbioherbicidal isolates of P. macrostoma was only 2.21% which was lower than that reported for other related Phoma sp. Other than the bioherbicidal trait, there was no apparent affiliation of the genetics with known varietal types, host or geographic origin. ITS sequence analysis and AFLP fingerprinting may be used as tools to detect bioherbicidal isolates of P. macrostoma.

A SNP-based PCR–RFLP capillary electrophoresis analysis for the identification of the varietal origin of olive oils

Authenticity and traceability of high quality monovarietal extra virgin olive oils is a major concern for markets and consumers. Although analytical chemistry techniques are widely used to satisfy these needs recently developed DNA-based methods can serve as complementary approaches. A SNP database comprising 10 Greek olive varieties was constructed and five SNPs, residing in restriction sites, were selected for the development of a PCR-RFLP capillary electrophoresis method to discriminate these varieties using leaf DNA as template. An identification key was constructed indicating that five SNPs were adequate to discriminate nine out of the 10 varieties. As a proof of principle the assay was applied on DNA extracted from five of their corresponding monovarietal olive oils. Three SNPs were able to identify the varietal origin of these olive oils confirming the validity of this approach.

Study of phenolic composition and sensory properties of red grape varieties in danger of extinction from the Spanish region of Castilla-La Mancha

This paper reports on a study of the profiles of different phenolic compounds (anthocyanins, flavonols, hydroxycinnamic acids and stilbenes) of five minor red grape varieties from the Spanish region of Castilla-La Mancha (Bobal, Moravia Agria, Moravia Dulce, Rojal and Tortosi) and a traditional variety from this growing region (Cencibel) as reference. Grape skin extracts of each variety were analysed by High Performance Liquid Chromatography coupled to Diode Array Detector (HPLC–DAD). The content of grape skins in anthocyanins (21.1–453 mg kg−1), flavonols (26.9–288 mg kg−1) and hydroxycinnamic acids (6.80–18.2 mg kg−1) showed differences according to mainly varietal origin, although other important factors have to be taken into account such as the degree of ripeness, berry size or vintage year. In all the studied varieties, the major anthocyanin was malvidin 3-glucoside (>40%) with the exception of Rojal variety, which major one was peonidin 3-glucoside together with cyanidin 3-glucoside. Moravia Dulce and Rojal varieties contained more than 46% of quercetin 3-glucuronide; the rest of them contained less than 27%. No relation was found between profiles of hydroxycinnamic acids in the studied samples and their variety or year of vintage. All the studied grapes presented high concentrations of stilbenes that could be interesting due to the health benefits.

Varietal Differentiation of Grape Juice Based on the Analysis of Near- and Mid-infrared Spectral Data

The aim of this study was to evaluate the usefulness of visible (VIS), near-infrared reflectance (NIR) and mid-infrared (MIR) spectroscopy combined with pattern recognition methods as tools to differentiate grape juice samples from commercial Australian Chardonnay (n = 121) and Riesling (n = 91) varieties. Principal component analysis (PCA), partial least squares discriminant analysis and linear discriminant analysis (LDA) were applied to classified grape juice samples according to variety based on both NIR and MIR spectra using full cross-validation (leave-one-out) as a validation method. Overall, LDA models correctly classify 86% and 80% of the grape juice samples according to variety using MIR and VIS-NIR, respectively. The results from this study demonstrated that spectral differences exist between the juice samples from different varietal origins and confirmed that the infrared (IR) spectrum contains information able to discriminate among samples. Furthermore, analysis and interpretation of the eigenvectors from the PCA models developed verified that the IR spectrum of the grape juice has enough information to allow the prediction of the variety. These results also suggested that IR spectroscopy coupled with pattern recognition methods holds the necessary information for a successful classification of juice samples of different varieties.

Evolution of anthocyanin profile from grape to wine

<p style="text-align: justify;"><strong>Aims</strong>: This study aimed at acquiring knowledge of the evolution of anthocyanins from grape to wine and the possibility of deducing the varietal origin of a wine from its anthocyanin profile.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The anthocyanin « fingerprint », or profile, of a series of autochthonous Sicilian accessions and their respective young wines was determined by HPLC-DAD in 2008. Data were evaluated by taking into account the evolution of the percentages of side-ring dioxygenated and tri-oxygenated anthocyanins, the ratio between acetylated and p-coumaroylated derivatives, and the principal component analysis (PCA) results. From grape to the end of alcoholic fermentation, the percentages of 3-glucosides of cyanidin, peonidin, delphinidin and p-coumaroylglucosides decreased, whereas those of malvidin-3-glucoside, acetylated derivatives and, in some cases, petunidin-3-glucoside increased. In many but not all wines, after malolactic fermentation, the percentages of p-coumaroylated derivatives decreased further and those of cyanidin- 3-glucoside and acetylated derivatives increased ; less variation was observed in malvidin-3-glucoside values.</p><p style="text-align: justify;"><strong>Conclusions</strong>: From grapes to young wines, the anthocyanin profiles varied mainly because of the activity of polyphenol oxidase (PPO), yeasts and lactic acid bacteria. However, they were substantially retained in wines from varieties in which tri-oxygenated side-ring anthocyanins prevailed, but were dramatically different from the respective grapes in wines from varieties rich in di-oxygenated anthocyanins, or in which the di-oxygenated forms prevailed over the tri-oxygenated ones. PCA analysis confirmed these findings.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Only in varieties in which the anthocyanin profile of grapes is characterized by low percentages of dioxygenated side-ring forms is it possible to gain information about the varietal origin of a young wine by comparing the profiles of both grape and wine. However, great care is required.</p>

Varietal discrimination of extra virgin olive oils by near and mid infrared spectroscopy

Abstract The use of near and mid infrared spectroscopy, combined with chemometric analysis, was explored as a tool to classify samples of Italian extra virgin olive oil on the basis of the cultivar. A total of 82 monovarietal samples (‘Casaliva’, ‘Leccino’ and ‘Frantoio’) of extra virgin olive oils were analysed. Several variables were measured: the free acidity, the peroxide value, spectrophotometric indices, the fatty acid composition, carotenoids, chlorophylls and tocopherol content. The same samples were also scanned by using NIR and MIR spectroscopy. The classification methods (LDA and SIMCA) were applied on chemical data and on the spectral data after having used the algorithm SELECT, as feature selection technique. The results showed that NIR and MIR spectroscopy is an interesting technique compared with traditional chemical index in classifying olive oil samples on the basis of the varietal origin. The spectroscopic methods could represent a reliable, cheap and fast classification tool, not requiring chemical analyses for discrimination among cultivars.

Volatile sulphur compounds composition of monovarietal white wines

The sulphur compounds composition of wines produced experimentally from six white cultivars (Alvarinho, Loureiro, Trajadura, Pedernã, Azal Branco and Avesso) was evaluated during two consecutive vintages. Results show that wines could be differentiated according to their sulphur compounds content. In general, Loureiro, Trajadura and Pedernã cultivars led to wines with low concentrations of sulphur compounds; however, Loureiro wines were characterised by significant amounts of dimethyl sulphone, whereas Trajadura wines possessed a high content of 3-(methylthio)propyl acetate and 4-(methylthio)-1-butanol. Alvarinho and Avesso wines showed high levels of S-methyl thioacetate, 3-mercapto-1-propanol, 3-(ethylthio)-1-propanol and 3-methylthiopropionic acid. Significant amounts of 2-methyltetrahydrothiophen-3-one, cis- and trans-2-methyltetrahydrothiophen-3-ol were also found in Avesso wines. Azal Branco wines were low in 3-(methylthio)propyl acetate and 2-(methylthio)ethanol, and high contents in S-methyl thioacetate, 3-mercapto-1-propanol and 2-mercaptoethanol. A linear discriminant analysis of sulphur compounds levels showed a differentiation of wines according to their varietal origin.

Characterization and Differentiation of Monovarietal Grape Marc Distillates on the Basis of Varietal Aroma Compound Composition

To investigate the varietal aroma compound composition of monovarietal grape marc distillates made from six different varieties (Vitis vinifera L.) in the region of Istria (Croatia), 30 samples were subjected to GC/MS and GC/FID analysis. A total of 73 compounds were identified: 45 monoterpenes, 20 sesquiterpenes, 3 diterpenes, and 5 C(13)-norisoprenoids. The largest number and the highest concentration of monoterpenes were found in Muscat Blanc, followed by Rose Muscat of Porec (Muskat ruza porecki) distillates, which were both characterized as highly aromatic. Lower, but still significant monoterpenol content was determined in distillates made from Istrian Malvasia (Malvazija istarska) grape marc. Chardonnay, Cabernet Sauvignon, and Teran distillates exhibited poorer monoterpene profiles, while Teran distillates contained elevated sesquiterpene concentrations. It was concluded that investigated monovarietal grape marc distillates significantly differ in varietal aroma compound composition. Stepwise linear discriminant analysis provided efficient discrimination models, and extracted various monoterpenes, sesquiterpenes and C(13)-norisoprenoids as important differentiators of distillates according to varietal origin.

Chemometric analysis of combined NIR and MIR spectra to characterize French olives

AbstractChemometric treatment of near‐infrared (NIR) and mid‐infrared (MIR) combined spectra was used firstly to predict oil and water contents in fresh olive fruit samples (n = 223) and secondly to classify these samples into five principal French cultivar origins (Aglandau, Cailletier, Olivière, Salonenque, and Tanche). The study was carried out during four crop years (2005/2006 to 2008/2009) to take into account the seasonal variations. The comparison of the results obtained in the combined range (REP = 2.6% for the water content and 3.5% for the oil content) provides an obvious advantage compared to the NIR and MIR techniques used separately. Fresh olive fruit cultivars were satisfactorily classified with the partial least squares‐discriminant analysis (PLS‐DA) method in the combined range. After use of the K‐means clustering on the PLS‐DA scores, all the samples were well classified into their five groups of origin. The use of infrared combined spectra allows a considerable improvement in estimating olive fruit quality (oil and water contents, varietal origins).

Variability in flavonol content of grapes cultivated in two Mediterranean islands (Sardinia and Corsica)

The main abundant flavonols, myricetin, quercetin and kaempferol, were analyzed in 58 samples of native red and white grapes from two Mediterranean islands, Sardinia and Corsica, with the aim of identifying a possible correlation between the respective flavonol profile and varietal origin. Quercetin and myricetin are the most commonly represented flavonols in the red grapes. In the white varieties quercetin prevails over kaempferol, while myricetin is absent. Absolute data show that the red varieties of Nielluccio and Minustello present high total concentrations of flavonols. Among the white grape varieties it is possible to observe that the Moscato is characterized by a total flavonol content clearly higher than that of Vermentino, and comparable to, sometimes even higher than, that of the other red varieties. No differences have been found between the Vermentino samples from Corsica and Sardinia according to their geographical origin. Considering the absolute values of the compounds analyzed great variability is found among the samples belonging to the same variety, whereas variability in the flavonol profile, expressed as percentage content of each aglycon of the total, is less pronounced. Statistical techniques (ANOVA and Hierarchical Cluster Analysis) showed that the flavonol profile, rather than the absolute values, enabled good discrimination between cultivars, demonstrating that it may effectively be used for chemotaxonomic aims.

Characteristics of Virgin Olive Oils from the Olive Zone of Extremadura (Spain), and an Approximation to their Varietal Origin

AbstractWe studied the differences in the characteristics that typify virgin olive oils produced in three representative zones of Extremadura: Sierra Norte of Cáceres, Serena–Siberia, and Tierra de Barros. A total of 156 samples from those three zones were assayed for fatty acids, triglycerides, sterols, and erythrodiol + uvaol. Statistically significant differences (p < 0.05) were found between the mean values of the parameters corresponding to the three zones. These profiles were then used to classify the varietal origin of the oils using the discriminant functions that had previously been defined by the authors for these parameters. This classification, together with the production data, confirmed the use of the different varieties of olives in the study zones. The results showed Manzanilla Cacereña to be the most used variety in the Sierra Norte of Cáceres zone, Cornezuelo and Verdial de Badajoz with a slight presence of Picual in the Serena–Siberia zone, and Carrasqueña and Morisca in Tierra de Barros.

A Double Mutation in the Anthocyanin 5-O-Glucosyltransferase Gene Disrupts Enzymatic Activity in Vitis vinifera L.

The inability of most European grapevines ( Vitis vinifera ) to produce 3,5-di-O-glucosides of anthocyanidin-3-O-glucosides while in other Vitis species diglucosides are found has long been used as a diagnostic tool for the classification of wines according to their varietal origin. A functional 5-O-glucosyltransferase (5GT) gene and its nonfunctional allele were recently cloned from the heterozygous hybrid cultivar 'Regent'. Protein sequence comparison revealed only five amino acid substitutions and a truncation at the C-terminus in the inactive enzyme. Restoration of the C-terminus in the European allele alone proved to be insufficient for a reversal to a functional allele. An additional V121L transition located in close spatial vicinity of the catalytically active histidine in the active site of the nonfunctional protein was also essential to recover 5GT activity. Thus, two mutations render the 5GT inactive in V. vinifera and explain why revertants for this mutant allele have not been observed in breeding programs. The results have a significant effect on the classification and breeding of Vitis varieties and the evaluation of derived products.

Key Compounds of Provence Rosé Wine Flavor

The aromas of French Provence rosé wines were subject to in-depth gas chromatography and sensory analyses at the Research and Experimentation Center on Rosé Wine (Centre de Recherche et d’Expérimentation sur le Vin Rosé). The study has demonstrated the olfactive contribution of different volatile compounds of fermentative and varietal origins. Dearomatization and reconstitution of flavor has revealed the preponderant character of ethyl esters and higher alcohol acetates, which are simple to determine and are at the origin of the fruity and amylic notes of rosé wines. Moreover, the search for specific varietal compounds—well known in other types of wines—has made it possible to identify some key compounds of rosé wine flavor: two volatile thiols (3-mercaptohexanol and 3-mercaptohexyl acetate), two furanic compounds (furaneol and homofuraneol), and one C13 norisoprenoid (β-damascenone). These compounds have now been measured in most of the experiments conducted at the Center on Rosé Wine and are used as qualitative indicators in evaluation protocols for the exploitation of vines or for rosé winemaking techniques.