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Wine Flavor Chemistry Flavor is the psychological interpretation of the physiological response to a physical stimulus Milton Bailey, University of Missouri, 1986
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2 -methoxy 3 isobutyl pyrazine (2 ppt) Identified in Bell Peppers (1969) Sensitive to light (1986) Method for quantifying : (2003) WHAT CAUSES VEGY FLAVOR in WINE?
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SENSORY PCA – 19 wines (1986)
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SOIL PCA
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PLS of Soil and Vineyard factors versus Sensory Noble and Elliot-Fiske, 1990
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Heymann (1986) Descriptive Analysis of Cabernet sauvignon
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Sivertsen, et al.(1999). Classification of French red wines according to geographical origin by of multivariate data analyses
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Fischer, et al. (1999) The impact of geographic origin, vintage and wine estate on sensory properties of Vitis vinifera cv. Riesling
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Karen Hein, 2005
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CANONICAL VARIATE ANALYSIS OF SPIKED WINE SAMPLES
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Morrison and Noble, 1990. Am. J. Enol. Vitic.41: 193 - 200. Cabernet sauvignon – differences too subtle to describe
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Fraction Light Vigor Pyrazine Bell Pepper Aroma Vegy Saga
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Evaluation of 96 Bordeaux red wines IBMP is the contributor to vegetal aroma in Cabernet sauvignon; Cabernet franc and Sauvignon blanc Compound only found in a minority of Merlot
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Compounds released in white wines 4-mercapto-4-methylpentan-2-one (4MMP) (also in Scheurebe) 0.8 ng/l*; range 0-40 -- box tree, broom flower; cat pee; conifer 4-mercapto-4-methylpentan-2-ol (4MMPOH) 55 ng/l*; range 0-150 -- citrus zest; grapefruit 3-mercapto-3-methylbutan-1-ol (3MMB) 1,500 ng/l*; range 30-150 – cooked leeks 3-mercaptohexan-1-ol (3MH) 60 ng/l*; range 200-5,000 – grapefruit; passion fruit; passion fruit skin 3-mercaptohexylacetate (3MHA) (also in Merlot, Cabernet sauvignon) 4.2 ng/l*; range 0-500 – box tree; passion fruit; sweet sweaty Aqueous 12% alcohol solution with 5g/l tartaric acid; pH 3.5 25 J, triangle; 50% correct increases during fermentation as these potent thiols released from their S-cysteine conjugate precursors Markers for great Sauvignon blanc
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Thiols in other varieties 4MMP and A3MH (3-mercaptohexylacetate [box tree]): Impact on aromas of Colombard and Muscat d’Alsace wines As well as on young wines from Petit manseng* 3MH Contributes passion fruit and grapefruit to Gewurtztraminer, Riesling, Petit manseng and botrytized Semillon * White variety, South West France – may be Albarino: floral fruity flavors, a distinct lemon and fruit salad flavor & high acidity increasing popularity in Languedoc & California Tominaga et al. (2000) AJEV 51(2):178-182
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Production, location and extraction of S-Cysteine Conjugates Moderate water stress favor S-cysteine conjugate (P-thiol) formation; severe prolonged stress limits production Location of P-thiolsdiffer as f(volatile thiol) P-4MMP and P-4MMPOH -- 80% in juice P-3MH – 50:50 between juice and skin Upto 19 hours skin contact Some ↑ in P-4MMP and P-4MMPOH (20% + 30%) 50% ↑ in P-3MH (even more extracted if skin contact at 18C vs 10C) Peyrot des Gachons, Catherine: Aroma Potential of Sauvignon blanc grapes, PhD Dissertation Bordeaux
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Transformation of p-thiols into varietal aromas Transformation % low (1 month after fermentation) – due to yeast lyases 1.4% for P-4MMP; 3% for P-4MMPOH; 4.2% for P-3MH Not much transformed? Or Lost? Or metabolized or unstable? – do not yet know Do know that P-thiol disappearance is correlated with thiol appearance Peyrot des Gachons, Catherine: Aroma Potential of Sauvignon blanc grapes, PhD Dissertation Bordeaux
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Norisoprenoids/norterpenoids from carotenes Beta-damascenone Shiraz stalky, earthy, cigar, and tobacco aromas black pepper aroma by GCO not id’d Cabernet Sauvignon and Merlot dried fig, tobacco and chocolate aromas Zinfandel Preliminary studies: Not much contribution Glycosides in Red varieties
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floral apple honey honey chocolate chocolate dried fig dried fig tobacco tobacco Base wine Napa Cabernet juice glycoside hydrolysate 0 1 2 3 4 Juice glycoside hydrolysate n=14 judges x 2 reps
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floral apple honey chocolate dried fig dried fig tobacco tobacco Base wine Napa Cabernet skin glycoside hydrolysate 0 1 2 3 4 Skin glycoside hydrolysate
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PLS of Aroma attributes versus volatiles floral apple honey dried fig chocolate tobacc o volatiles juices skin extracts Component 1 Component 2
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Volatiles related to the honey attribute Norisoprenoids: damascenone hydroxydamascone dehydro ß ionone TDN vitispirane actinidol Benzene derivatives: vanillin acetovanillone cinnamic acid Monoterpenes: ocimenol furan linalool oxide an ene diol Others: acetyl furan ethyl decanoate diethyl propanedioate
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PLS of Aroma attributes versus volatiles floral apple honey volatiles juices skin extracts Component 1 Component 2 dried fig chocolate tobacc o
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Volatiles associated with dried fig/tobacco Benzene derivatives: syringic acid ethyl syringate a methoxy phenol Monoterpenes: trimethyl vinyltetrahydropyran furan linalool oxide Others: two unknowns heptanoic acid hexadecanoic acid 2-Et-3-Me maleic anhydride
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Trellising or leaf removal increases light < 2-methoxy 3 isobutyl pyrazine > norisoprenoids Maturity How to assess pH, TA, °B? Grape Must Evaluation (evaluate in < 1 hour) Rinse and Crush grapes, add 20 ppm SO2 Homogenize skins/juice versus juice Grape Berry Evaluation Vineyard Variables:
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Temperature: Cool: retain more volatiles Warmer: more esters but lose more (fruity) low MW Yeast strain:? Biggest issue is H2S production “Natural” versus inoculation Skin Contact Time/Cap Management Increase K, pH, phenols, anthocyanins Centrifuging? FERMENTATION
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Terpene glycosides hydrolyze, but terpenes interconvert to less fruity forms Vitaspirane and 1,1,6 trimethyl 1,2 dihydronaphthalene increase Esters hydrolyze slowly: Acetate esters & higher MW faster. Acids esterify; pH ; Tannins polymerize Oxidation reactions AGING
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Extraction of volatiles: vanillin, eugenol, oak lactone Extraction: phenols, acids, lignins, CHO Oak Aging
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Oak aging continued VARIABLES: Source oak (Am Vanillin; Fr Phenols, extract) Sawn vs split Air vs kiln drying Air Vanillin; Kiln HMF Air drying in cool vs hot area Hot Vanillin,Oak lactone Hot vanilla, caramel, buttery Steamed or bent over fire Degree toasting Furfural, Vanillin
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