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Wine Flavor Chemistry

Wine Flavor Chemistry. Flavor is the psychological interpretation of the physiological response to a physical stimulus Milton Bailey, University of Missouri, 1986. WHAT CAUSES VEGY FLAVOR in WINE?. 2 -methoxy 3 isobutyl pyrazine (2 ppt) Identified in Bell Peppers (1969)

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Wine Flavor Chemistry

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  1. Wine Flavor Chemistry • Flavor is the psychological interpretation of the physiological response to a physical stimulus • Milton Bailey, University of Missouri, 1986

  2. WHAT CAUSES VEGY FLAVOR in WINE? 2 -methoxy 3 isobutyl pyrazine (2 ppt) Identified in Bell Peppers (1969) Sensitive to light (1986) Method for quantifying : (2003)

  3. SENSORY PCA – 19 wines (1986)

  4. SOIL PCA

  5. PLS of Soil and Vineyard factors versus Sensory Noble and Elliot-Fiske, 1990

  6. Heymann (1986) Descriptive Analysis of Cabernet sauvignon

  7. Sivertsen, et al.(1999). Classification of French red wines according to geographical origin by of multivariate data analyses

  8. Fischer, et al. (1999) The impact of geographic origin, vintage and wine estate on sensory properties of Vitis vinifera cv. Riesling

  9. Karen Hein, 2005

  10. CANONICAL VARIATE ANALYSIS OF SPIKED WINE SAMPLES

  11. Cabernet sauvignon – differences too subtle to describe Morrison and Noble, 1990. Am. J. Enol. Vitic.41: 193 - 200.

  12. Vegy Saga Fraction Light Vigor Bell Pepper Aroma Pyrazine

  13. 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

  14. Compounds released in white wines Markers for great Sauvignon blanc 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

  15. 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

  16. 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

  17. 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

  18. Glycosides in Red varieties 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

  19. Juice glycoside hydrolysate Napa Cabernet juice glycoside hydrolysate floral 4 Base wine 3 tobacco 2 apple 1 0 honey dried fig chocolate n=14 judges x 2 reps

  20. Skin glycoside hydrolysate Napa Cabernet skin glycoside hydrolysate 4 floral Base wine 3 tobacco apple 2 1 0 dried fig honey chocolate

  21. PLS of Aroma attributes versus volatiles Component 2 volatiles honey floral juices dried fig apple tobacco skin extracts chocolate Component 1

  22. Volatiles related to the honey attribute • Norisoprenoids: • damascenone • hydroxydamascone • dehydro ß ionone • TDN • vitispirane • actinidol • Benzene derivatives: • vanillin • acetovanillone • cinnamic acid • Others: • acetyl furan • ethyl decanoate • diethyl propanedioate • Monoterpenes: • ocimenol • furan linalool oxide • an ene diol

  23. PLS of Aroma attributes versus volatiles volatiles honey Component 2 floral juices dried fig apple tobacco chocolate skin extracts Component 1

  24. Volatiles associated with dried fig/tobacco • Benzene derivatives: • syringic acid • ethyl syringate • a methoxy phenol • Others: • two unknowns • heptanoic acid • hexadecanoic acid • 2-Et-3-Me maleic anhydride • Monoterpenes: • trimethyl vinyltetrahydropyran • furan linalool oxide

  25. Vineyard Variables: 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

  26. FERMENTATION 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?

  27. AGING 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

  28. Oak Aging Extraction of volatiles: vanillin, eugenol, oak lactone Extraction: phenols, acids, lignins, CHO

  29. 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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