Regulated deficit irrigation can improve grape quality, affecting wine aroma and taste by altering metabolite and glucan composition, with little, if any, loss in production (9, 10, 24, 27, 28, 38). Grapes exposed to water-deficits have higher concentrations of total phenolics and anthocyanins (10, 27, 38). Water-deficit treatments affected sensory perception of wine, altering visual, aromatic and flavor components (28). Post-harvest wilting of grapes and UV irradiation increased concentrations of resveratrol in the grapes (46). However, it is unclear in water-deficit-treated vines, which specific polyphenols increase in the grapes. Further research is warranted on the metabolite profiles of water-deficit-treated grapes. Water usage is a major concern to many growers, particularly those in NV, from both an economic and quality point of view. Controlled irrigation can not only save water, but also have a positive impact on the quality of wine made from grapes grown in semi-arid regions. The preliminary data gained in this research will provide key data that will allow us to clearly or definitively document the benefits of water deficit on grape must and wine quality.
Health Benefits of Wine: Although the consumption of alcohol is controversial, it is now well established that the consumption of wine at moderate levels has undeniable health benefits including the reduction of risk of cardiovascular disease, stroke and cancer (8, 14, 18, 29). In particular, red wine seems to have the most benefits. Phenolics in wines are major contributors to these health benefits. These compounds are particularly high in red wine (14) and their amounts can be increased in the berries by exposure to light and water-deficit (17, 24, 25, 46).
The majority of the 200+ grape polyphenols are located in the skin and seeds of the berry. Red grapes have much higher concentrations of polyphenols than white grapes (14). Furthermore, vinification influences the amount of extraction from the skins. Red wines have much longer skin extraction times than white wines (days to weeks for reds vs. 24 h or less for whites), which contribute to the higher polyphenol content of red wines.
The effects of wine polyphenols and ethanol on reduced risk of heart disease have been linked to increases in high-density lipoproteins (HDLs), inhibition of oxidation of low-density proteins (LDLs), reduced platelet aggregation, and increased vasodilation (14). Independent of the effects of alcohol, wine extracts inhibit endothelin-1 synthesis, a potent peptide causing vasoconstriction (5). This effect was correlated to total polyphenol content. Red wines were able to reduce endothelin-1 synthesis to a much greater extent than red-grape juice or white wines. The mechanism of action is unclear. The effects do not appear to be associated with the antioxidant properties of wine polyphenols, since at the red wine concentrations tested, neither the red wine polyphenols (quercitin, resveratrol, D,L-catechin, and D,L-epicatechin) nor the anthocyanins (delphinidin, pelargonidin, cyanidin, peonidin, petunidin, and malvidin) affected endothelin-1 synthesis. Resveratrol, a polyphenol and a phytoalexin, acts as a phytoestrogen (13) and an antioxidant (49). In animals and in vitro studies, resveratrol has been shown to have significant anti-inflammatory, anti-carcinogenic properties and helps prevent cardiovascular disease (4, 6, 20, 40, 49). Other wine polyphenols, such as quercitin and catechins, also act as antioxidants, contribute to vasodilation (4), and help prevent cardiovascular disease (6) and cancer (22, 40).
Flavor Analysis and Composition of Grape Musts: An entire book has been written on the methods for analysis of musts (fresh grape juice) and wines (32), much of which has vastly changed with new technology. Wine flavor is determined principally from a complex assortment of hundreds of volatile and non-volatile compounds derived from flavorless glycosidically bound precursors (37) and phenolics (32). Flavor compounds can also arise from primary metabolites, chlorophyll or carotenoid degradation products, or secondary metabolites of the shikimic acid (e.g., aromatic amino- benzoic-, and cinnamic acids, and lignins) and mevalonic acid (e.g., monoterpenoid) pathways. In white wines and red wines, major volatile precursors consist largely of monoterpenes, norisoprenoids, benzene derivatives, and aliphatic compounds (12, 37). In red wines, there are additional major classes of flavor compounds, many of which are skin and seed derived, include anthocyanins, anthocyanogens, catechins, flavonols, flavanones, and benzoic and cinnamic acid derivatives (32).
Flavonoid and nonflavonoid phenolic compounds: The anthocyanins are the only significant pigments in red grapes. The five major anthocyanins are delphinidin, pelargonidin, cyanidin, peonidin, petunidin, and malvidin. These compounds are found as glycosides. The anthocyanogens and catechins are polymerized and known as condensed tannins. Flavonols are usually present as glycosides. All of these phenolic compounds are found in the grape skins. The flavanones come from the seeds. The flavonoid phenolic compounds are the main components of red wine flavor. The nonflavonoid phenolic compounds from grapes consist of benzoic and cinnamic acid derivatives. Phenolic compounds are synthesized through the shikimic acid pathway. The main branch point of this pathway from primary metabolism to secondary metabolism is regulated by phenylalanine ammonia lyase (PAL). PAL activity is influenced by a number of environmental conditions including light.
Volatile and non-volatile glycosidically bound compounds: Over 200 volatile compounds were identified from enzyme- and acid-hydrolysates of the red grapes, Cabernet Sauvignon and Merlot (12). The dominant class of volatiles in the juice was the benzene derivatives, followed by the norisoprenoids, aliphatic compounds, and monoterpenes. Some of the compounds were associated with honey, fig, tobacco and chocolate flavors. In the white grape, Chardonnay, 180 volatile compounds from enzyme- and acid-hydrolysates were identified (37). The dominant class of volatiles in the juice was the norisoprenoids, followed by the benzene derivatives and the monoterpenes. Specific volatile compounds in Chardonnay wine are correlated with certain flavors (2). For example, 3-methylbutyl acetate was associated with green apple and pear aroma, linalool with citrus aroma, and 1,1,6-trimethyl-1,2-dihydronapthalene (TDN-I) with honey aroma. Most of the volatile compounds are synthesized through the terpenoid pathway. Isopentenyl pyrophosphate and dimethylallyl pyrophosphate are the major building blocks for this pathway and they come from two pathways in plants, the mevalonic acid pathway and the 3-phosphoglycerate/pyruvate pathway.
Metabolite profiling is an extremely powerful approach to extend and enhance information gathered by genomics and proteomic studies (11, 15, 16, 44, 45). In contrast to transcriptome or proteome analyses, biochemical complexity of metabolites precludes the use of any single analytical technique. The biochemical complexity of wine flavor and aroma determinants is well established and are determined principally from a complex assortment of hundreds of volatile and non-volatile compounds derived from flavorless glycosidically bound precursors (37) and phenolics (32).
Water deficit can improve grape composition and wine characteristics, particularly leading to increased levels of phenolics. Despite this complexity, we have found that by comparing the metabolite profiles of fruit extracts from well-watered and water-deficit treated grapes, we are able to detect both qualitative and quantitative differences in metabolite content. Metabolite profiles will be compared to transcript profiles in an attempt to establish the genetic basis of different wine characteristics.
Literature Cited:
1. Adrian M, Jeandet P, Douillet-Breuil AC, Tesson L, Bessis R (2000) Stilbene content of mature Vitis vinifera berries in response to UV-C elicitation. J Agric Food Chem 48: 6103-5.
2. Arrhenius SP, McCloskey LP, Sylvan M (1996) Chemical markers for aroma of Vitis vinifera var Chardonnay regional wines. Journal of Agricultural & Food Chemistry 44: 1085-1090
3. Baltenweck-Guyot R, Trendel JM, Albrecht P, Schaeffer A (2000) Glycosides and phenylpropanoid glycerol in vitis vinifera cv. Gewurztraminer wine. J Agric Food Chem 48: 6178-82.
4. Burns J, Gardner PT, O'Neil J, Crawford S, Morecroft I, McPhail DB, Lister C, Matthews D, MacLean MR, Lean MEJ, Duthie GG, Crozier A (2000) Relationship among antioxidant activity, vasodilation capacity, and phenolic content of red wines. J Agric Food Chem 48: 220-230
5. Corder R, Doutwaite JA, Lees DM, Khan NQ, Santos ACVD, Wood EG, Carrier MJ (2001) Endothelin-1 synthesis reduced by red wine. Nature 414: 863-864
6. Das DK, Sato M, Ray PS, Maulik G, Engelman RM, Bertelli AA, Bertelli A (1999) Cardioprotection of red wine: role of polyphenolic antioxidants. Drugs Exp Clin Res 25: 115-20
7. De Freitas VAP, Glories Y, Bourgeois G, Vitry C (1998) Characterisation of oligomeric and polymeric procyanidins from grape seeds by liquid secondary ion mass spectrometry. Phytochemistry 49: 1435-1441
8. de Lorimier AA (2000) Alcohol, wine, and health. Am J Surg 180: 357-61.
9. Esteban MA, Villanueva MJ, Lissarrague JR (1999) Effect of irrigation on changes in berry composition of Tempranillo during maturation. Sugars, organic acids, and mineral elements. American Journal of Enology & Viticulture 50: 418-434
10. Esteban MA, Villanueva MJ, Lissarrague JR (2001) Effect of irrigation on changes in the anthocyanin composition of the skin of cv Tempranillo (Vitis vinifera L) grape berries during ripening. Journal of the Science of Food & Agriculture 81: 409-420
11. Fiehn O, Kopka J, Dörmann P, Altmann T, Trethewey RN, Willmitzer L (2000) Metabolite profiling for plant functional genomics. Nature Biotechnology 18:
12. Francis IL, Kassara S, Noble AC, Williams PJ (1998) The contribution of glycoside precursors to Cabernet Sauvignon and Merlot aroma. In AL Waterhouse and SE Ebeler eds., Chemistry of Wine Flavor. ACS Symposium Series 714. American Chemical Society, New York, pp 13-30
13. Gehm BD, McAndrews JM, Chien PY, Jameson JL (1997) Resveratrol, a polyphenolic compound found in grapes and wine, is an agonist for the estrogen receptor. Proc Natl Acad Sci U S A 94: 14138-43.
14. German JB, Walzem RL (2000) The health benefits of wine. Annu Rev Nutr 20: 561-93.
15. Glassbrook N, Beecher C, Ryals J (2000) Metabolic profiling on the right path. Nat Biotechnol 18: 1142-3.
16. Glassbrook N, Ryals J (2001) A systematic approach to biochemical profiling. Curr Opin Plant Biol 4: 186-90.
17. Gollop R, Farhi S, Perl A (2001) Regulation of the leucoanthocyanidin dioxygenase gene expression in Vitis vinifera. Plant Sci 161: 579-588
18. Gronbaek M, Becker U, Johansen D, Gottschau A, Schnohr P, Hein HO, Jensen G, Sorensen TI (2000) Type of alcohol consumed and mortality from all causes, coronary heart disease, and cancer. Ann Intern Med 133: 411-9.
19. Guedes de Pinho P, Silva Ferreira AC, Mendes Pinto M, Benitez JG, Hogg TA (2001) Determination of carotenoid profiles in grapes, musts, and fortified wines from Douro varieties of Vitis vinifera. J Agric Food Chem 49: 5484-5488
20. Gusman J, Malonne H, Atassi G (2001) A reappraisal of the potential chemopreventive and chemotherapeutic properties of resveratrol. Carcinogenesis 22: 1111-7.
21. Hoenicke K, Simat TJ, Steinhart H, Kohler HJ, Schwab A (2001) Determination of free and conjugated indole-3-acetic acid, tryptophan, and tryptophan metabolites in grape must and wine. J Agric Food Chem 49: 5494-501.
22. Kampa M, Hatzoglou A, Notas G, Damianaki A, Bakogeorgou E, Gemetzi C, Kouroumalis E, Martin PM, Castanas E (2000) Wine antioxidant polyphenols inhibit the proliferation of human prostate cancer cell lines. Nutr Cancer 37: 223-33.
23. Kennedy JA, Hayasaka Y, Vidal S, Waters EJ, Jones GP (2001) Composition of grape skin proanthocyanidins at different stages of berry development. J Agric Food Chem 49: 5348-55.
24. Kennedy JA, Matthews MA, Waterhouse AL (2000) Changes in grape seed polyphenols during fruit ripening. Phytochemistry 55: 77-85
25. Kolb CA, Kaser MA, Kopecky J, Zotz G, Riederer M, Pfundel EE (2001) Effects of natural intensities of visible and ultraviolet radiation on epidermal ultraviolet screening and photosynthesis in grape leaves. Plant Physiol 127: 863-75.
26. Mateus N, Silva AM, Vercauteren J, de Freitas V (2001) Occurrence of anthocyanin-derived pigments in red wines. J Agric Food Chem 49: 4836-40.
27. Matthews MA, Anderson MM (1988) Fruit ripening in Vitis vinifera L.: Responses to seasonal water deficits. Am J Enol Vitic 39: 313-320
28. Matthews MA, Ishii R, Anderson MM, O'Mahony M (1990) Dependence of wine sensory attributes on vine water status. J Sci Food Agr 51: 321-335
29. Middleton E, Kandaswami C, Theoharides TC (2000) The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer. Pharmacol Rev 52: 673-751.
30. Noble AC (1996) Taste-aroma interactions. Trends in Food Science & Technology 7: 439-444
31. Nyman NA, Kumpulainen JT (2001) Determination of anthocyanidins in berries and red wine by high- performance liquid chromatography. J Agric Food Chem 49: 4183-7.
32. Ough CS, Amerine MA (1988) Methods for Analysis of Musts and Wines. 2nd edition John Wiley &Sons, New York.
33. Peyrot Des Gachons C, Tominaga T, Dubourdieu D (2000) Measuring the aromatic potential of Vitis vinifera L. Cv. Sauvignon blanc grapes by assaying S-cysteine conjugates, precursors of the volatile thiols responsible for their varietal aroma. J Agric Food Chem 48: 3387-91.
34. Pozo B, Pueyo E, Martin-Alvarez PJ, Polo MC (2001) Polydimethylsiloxane solid-phase microextraction-gas chromatography method for the analysis of volatile compounds in wines. Its application to the characterization of varietal wines. J Chromatogr A 922: 267-75.
35. Roessner U, Luedemann A, Brust D, Fiehn O, Linke T, Willmitzer L, Fernie A (2001) Metabolic profiling allows comprehensive phenotyping of genetically or environmentally modified plant systems. Plant Cell 13: 11-29.
36. Roessner U, Willmitzer L, Fernie AR (2001) High-resolution metabolic phenotyping of genetically and environmentally diverse potato tuber systems. Identification of phenocopies. Plant Physiol 127: 749-64.
37. Sefton MA, Francis IL, Williams PJ (1993) The volatile composition of chardonnay juices: A study by flavor precursor analysis. Am J Enol Vitic 44: 359-370
38. Sipiora MJ, Granda MJG (1998) Effects of pre-veraison irrigation cutoff and skin contact time on the composition, color, and phenolic content of young Cabernet Sauvignon wines in Spain. Am J Enol Vitic 49: 152-162
39. Steel CC, Keller M (2000) Influence of UV-B irradiation on the carotenoid content of Vitis vinifera tissues. Biochem Soc Trans 28: 883-5.
40. Surh YJ, Chun KS, Cha HH, Han SS, Keum YS, Park KK, Lee SS (2001) Molecular mechanisms underlying chemopreventive activities of anti- inflammatory phytochemicals: down-regulation of COX-2 and iNOS through suppression of NF-kappa B activation. Mutat Res 480-481: 243-68.
41. Tominaga T, Baltenweck GR, Des GCP, Dubourdieu D (2000) Contribution of volatile thiols to the aromas of white wines made from several Vitis vinifera grape varieties. American Journal of Enology and Viticulture. 51: 178-181
42. Tominaga T, Blanchard L, Darriet P, Dubourdieu D (2000) A powerful aromatic volatile thiol, 2-furanmethanethiol, exhibiting roast coffee aroma in wines made from several Vitis vinifera grape varieties. J Agric Food Chem 48: 1799-802.
43. Torres JL, Bobet R (2001) New flavanol derivatives from grape (Vitis vinifera) byproducts. Antioxidant aminoethylthio-flavan-3-ol conjugates from a polymeric waste fraction used as a source of flavanols. J Agric Food Chem 49: 4627-34.
44. Trethewey RN (2001) Gene discovery via metabolic profiling. Curr Opin Biotechnol 12: 135-8.
45. Trethewey RN, Krotzky AJ, Willmitzer L (1999) Metabolic profiling: a Rosetta Stone for genomics? Curr Opin Plant Biol 2: 83-5.
46. Versari A, Parpinello GP, Tornielli GB, Ferrarini R, Giulivo C (2001) Stilbene compounds and stilbene synthase expression during ripening, wilting, and UV treatment in grape cv. Corvina. J Agric Food Chem 49: 5531-5536.
47. Waffo-Teguo P, Lee D, Cuendet M, Merillon J, Pezzuto JM, Kinghorn AD (2001) Two new stilbene dimer glucosides from grape (Vitis vinifera) cell cultures. J Nat Prod 64: 136-8.
48. Wirth J, Guo W, Baumes R, Gunata Z (2001) Volatile compounds released by enzymatic hydrolysis of glycoconjugates of leaves and grape berries from Vitis vinifera Muscat of Alexandria and Shiraz cultivars. J Agric Food Chem 49: 2917-23.
49. Wu JM, Wang ZR, Hsieh TC, Bruder JL, Zou JG, Huang YZ (2001) Mechanism of cardioprotection by resveratrol, a phenolic antioxidant present in red wine. Int J Mol Med 8: 3-17.