Studies have been carried out on red and white monovarietal wines vinified during the 1995, 1996 and 1997 harvests. The essential aim being to evaluate sensory quality, correlate it with chemical analytical data and relate these to the various winemaking options available. Hence selective native varieties from the Douro, Dao, Bairrada and Vinhos Verdes regions have been studied and the analytical / sensorial data correlated to such factors as grape maturation and
maceration regime. Results are presented illustrating the quality effects of variety / winemaking practice combinations, both in terms of analytical data (sensory and chemical) and taster preferences

Cabral, L.

Guedes, P.

Hogg, T.

Pessanha, M.

Pina, C.

Santos, C.

Silva, M. C. M.

Soares Franco, J. M.

Vasconcelos, I.

Vieira, M.

English

Repositório Institucional da Universidade Católica Portuguesa

DEFINING THE UNIQUENESS OF MONOVARIETAL WINES FROMNATIVE PORTUGUESE VARIETIES OF Vitis vinifera' Guedes, P.; Pina, C.; Santos, C.; Vasconcelos, I.; Silva, M.C.M. & Hogg, T.;Cabral, L.; Vicira, M.; Pessanha, M. & Soares Franco, J.M.Universidadc CatOlica Portuguesa - Escola Superior de Biotecnologia, R. Dr. AntOnio Bernardino de Almeida,4200 PORTO, PortugalSOGRAPE Vinhos de Portugal., Aldeia Nova de Avintes, 4400 V. N. GAZA, PortugalABSTRACTStudies have been carried out on red and white monovarietal wines vinified during the 1995,1996 and 1997 harvests. The essential aim being to evaluate sensory quality, correlate it withchemical analytical data and relate these to the various winemaking options available. Henceselective native varieties from the Douro, Dao, Bairrada and Vinhos Verdes regions have beenstudied and the analytical / sensorial data correlated to such factors as grape maturation andmaceration regime. Results are presented illustrating the quality effects of variety / winemakingpractice combinations, both in terms of analytical data (sensory and chemical) and tasterpreferences.KEY WORDS: Portuguese varieties, winemaking, aromaINTRODUCTIONAs a traditional wine producing country, Portugal possesses a long established "appellation -system in which official bodies attempt to define and control the regional characteristics ofwine styles. The varieties encountered within these demarcated regions are consideredcharacteristic and although in some cases certain native varieties have close relatives in other(predominantly southern European) regions, most are apparently unique to Portugal. Many ofthese varieties can produce wines of high quality and export market acceptability, despite thislittle is known about these varieties apart from basic ampelographic descriptions. Each regionuses distinct varieties of Vitis vinifiera grapes in the production of its wines, although thecommercialisation of wines from single varieties is rare in this context, the majority are blendswhich, at their best, are carefully prepared to accentuate regional and quality characteristics.Despite the fact that such wines are not generally commercialised it is considered essential thatsingle varieties are used when studying the characteristics of regional wines.Thus the wines used in this study were derived from 4 different viticultural regions of centraland northern Portugal namely Dao, Bairrada, Douro and Vinhos Verdes. In this study the grapesand/or wines were also submitted to various enological procedures namely different states ofgrape maturation, grape maceration trials, fermentation in oak vessels and utilisation of selectedstrains for malolactic and alcoholic fenntations. Presented here are selected results from the1995, 1996 and 1997 harvests. The study of the Dao region includes red and white wines whilstthe study of the other regions only includes white wines. All wines were analysed for standardenological parameters, for volatile profiles (GC), selected volatile compounds (monoterpcnes,higher alcohols and esters) and were submitted to a rigorous sensorial analysis by a panel oftrained tasters. The results were submitted to a statistical evaluation.MATERIALS AND METHODS— Grape varieties Dao regionwhite grapes: Encruzado and Assario, red grapes: Touriga Nacional and JaenBairrada regionMaria Comes, Cercial, Arinto and BicalDouro regionFemäo Pires, °Mega, Gouveio, Malvazia Fina and ViozinhoVinhos Verdes regionLoureiro, Pederna and Trajadura— Vinification Wines were obtained from fruit processed by SOGRAPE. Various scales of vinification wereemployed: micro ( 20 L ), mini ( 350 L) and commercial scale (  5000 L), depending on theavailability of suitable grape material and general winemaking or experimental considerations.The grape maturation studies were conducted on red and white varieties of the DA° regionat 3 different levels of probable alcohol content (I I, 12 and 13° baurne), grapes being harvestedfrom an experimental vineyard site.Skin contact studies (12 h at 4° C) were performed with white varieties from Vinho Verdeand Bairrada regions, some assays being conducted with addition of extracts of enzymes.Chemical analysesstandard enological parameters (pH, ethanol concentration, total and volatile acidity and totaland free S02) following the Portuguese standard.GC analysisvolatile fermentation derived compounds and terpenes following the method of Bertrand (1981)Higher alcohols, ethanal, ethyl acetate and methanol following the method of Bertrand (1994)HPLC analysisorganic acids (Dionex, following manual instructions)aminoacids (post-column ninhydrin derivatization, method described on manual instructions).Sensory analysis All wines were tasted "blind" by a professional panel from SOGRAPE and ESB with a totalof 14 tasters - a minimum of 8 being present at each session. Specific and semi quantitativescoring was employed using a tasting sheet containing 21 items (2 visual, 13 olfactory and 6gustatory).Statistical analysisCorrelation between sensory and analytical data is achieved employing a Principal ComponentAnalysis (PCA). This method calculates linear combinations of variables, this allows theoriginal multidimensional matrix to be simplified making easier the interpretation of complexdata. The results of PCA can be graphically displayed as two sets of plots. The software employedwas the STAT-ITCF.RESULTSSelected results are presented below showing the major findings and tendencies of the studies11784TI I -Touriga Nacional I I""II 2- 'Iouriga Nacional 12"TI2(r)- TN I 2 repetition11 1-Jacit I I"11 I (r)-Jaen I I° repetitionII 3 - Touriga Nacional I VAXIS 2rI3Aromatic persistenceLinaloolFloralTI 2 (r)AXIS I.11 l(r)111%nu Hatincs1/4Ethyl lacticTI2I) The influence of grave maturation state on the quality of wines from Duo region.la) Red wines— Analysis of the sensory data indicates a clear preference for Touriga Nacional 12 (TN 12)and TN 13, which have the higher levels in ethyl esters, acetates, higher alcohols, free flutyacids, as well as in linalool and terpeniol contents (Fig. I and 2)Touriga Nacional 13 was considered the softest wine with the greater "volume".The wines with the lowest level of maturation (TN 11) were classified as "vegetal" and"acid". These wines contain low levels of linalool and ethyl esters.Jaen wines were generally poor in free terpene compounds and in volatile fermentationcompounds. These wines were sensorially classified as "vegetal" and acidic.AXIS 2AXIS IFLO - FloralSUA - SmoothnessACI - AcidityVEG-Yeget alCOR- ColourPER - PersistenceFRS- Dried fruitseet- ethyl estersace-acetatesacet- ethyl acetatemet-methanolI in-linaloolterp-tcrpencolFigurel. Selected chemical and sensory variables identified in red Däo wines projected onthe plane formed by axes 1 and 2.Figure 2. Projection of Me red wines on the plane formed by the axes I and 2. The numbers11, 12 and 13 refer to the Baum& values at harvest.II-X511.0 FloralSIR - Sinoottmes.ACI - Acidity- VolumeTQ - Total QualityPER-PersistenceAXIS 2I inFLOSt AV()alcaccta-xFruityA torTlatktpersistence hex-hexanollin-linaloolalc- alcoholaces- ethyl acetateace-acetatesAXISAcidityI lexanolACIPERTQlb)AfAario and Encruzado white wines with low levels of maturation (AS 11 and EN 11) wereclassified as the most acid wines and with the higher levels of hexanol (Fig. 3 and 4).- Sznisorially the wine with the higher classification was the En 12 which was the most fruityand with the higher aromatic persistence (Fig. 4).I ' i gnite 3. Projection of selected chemical and sensory variables on the plane formed byaxes 1 and 2.    AXIS 2           Eli  A 1 1A 1Itr)AX/s 	   A I I -Assari oAI I (El- Assario repetition      E 1 1-Encruzado 11El 1 -Eneruzado 12E 1 2	 F 1 2(r)- Encruzado 12F 2(r)	 repetition1:13- Encruzado 13      E IAl W level of maturation Lio                  Figure 4. Projection of Drip white wines on the plane formed by the axes I and 111-86AXIS 2AXIS IFLO - FloralSUA - SmoothnessACt - AcidityVOL - VolumePER - PersistenceTQ - Total Qualityact- total acidityamt- amyl alcoholshex-hexanollin-linaloolterp-terpenioleta-ethanalalc-alcohollet - ethyl lactateLo - LoureiroLomp - Loureiro withskin contactLome-Loureiro skincontact with enzymePe - PedernäRi	 4;,: i	't!	 intritt-'4:7h .4,rtCod-CodegaFP-Femäo PircsMF-Malvazia FinaGou-GouvcioVio-ViozinhoLomeVinhos Verdes lieu e ti:ft	 DouroAXIS 2 MFII) Characterization of wines from white varieties from the Bairrada. Douro and Vinhos Verdesregions and the influence selected enological practicesFigures below show the differentiation of the white wines from Bairrada, Douro and VinhosVerdes regions (Fig. 6) and the characteristics which were used to separate them (Fig. 5). Theeffect of skin contact and enzyme treatment from the Maria Gomes and Loureiro varieties arethus included on figure 6.Figure 5. Projection of selected chemical and sensorial variables on the plane formed by axis1 and 2.Figure 6. Projection of Bairrada, Douro and Vinho Verde white wines on the plane formedby the axes I and 2.11-87Axis 2 is made up of variables such as linalool, terpeniol, total quality (TQ) and persistence(PER). The Maria Gomes wines from Bairrada region show a strong floral and fruity characterand are alligned on this axis. Distant from these wines we can see those of Bical, Arinto andCercial from the same region which are characterised by low levels of linalool and terpeniolThe wines from Vinho Verde region are distinguished from the wines from Bairrada andDouro regions due to sensorial acidity (ACI), chemical acidity (Act), "floral" character (FLO)and hexanol concentration (Hex) (Fig. 6).The Loureiro wine with skin contact and with enzyme treatment was clearly differentiatedfrom the others due to the higher levels of terpene compounds (linalool and terpeniol).In figure 5 the axis 1 is made by variables such as volume, alcohol, ethyl lactate and"softness" and "roundeness". Douro wines are projected on this axis. Wines from Fernao Piresvariety (synonymous with the Maria Gomes variety from Bairrada) were the most aromaticwines from the Douro region.CONCLUSIONSIt is underiable that many native Portuguese varieties of Vitis vinifera produce wines withdistinct and attractive characteristics. The lack of descriptive data concerning the aroma activecompounds in these varities certainly limit the winemaking options. The results presented heresuggest that the methodology employed and the techniques used are appropriate to identify thearoma and flavor characteristics and substances which contribute to them.Although certain tendencies have already been suggested further analysis will be required tofully understand the potential of these varieties.BIBLIOGRAPHYBertrand A. (1981). Formation des substances volatiles au cours de la fermentation alcoolique.Incidence sur la qualitê des vins. Colloque Soc. Fr. Microbiol., Reims, 251-267.Bertrand A. (1994). Dosage des alcools suparieurs des eaux de vie. Recueil des methodesd'analyses des eaux de vie.Ribereau-Gayon P., Boidron J.N., Terrier A. (1975). Aroma of muscat grape varieties. J. Agric.Food Chem., 23, (6), 1042-1047.STAT-ITCF. Institut Technique des Cêrêales et des Fourrages. 8, Av. du Prèsident Wilson,75116 Paris.11-88

Defining the uniqueness of monovarietal wines from native portuguese varieties of Vitis vinifera

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Defining the uniqueness of monovarietal wines from native portuguese varieties of Vitis vinifera

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