Maturity, grape

Czochanska, Z., Foo, L., and Porter, L., Compositional changes in lower molecular weight flavans during grape maturation. Phytochemistry 18, 1819, 1979. 

The bacterial conversion of malic acid to lactic acid and carbon dioxide has been recognized since 1890 and is referred to as the malo-lactic fermentation. This conversion has been promoted under controlled conditions in the cooler viticultural regions of the world where grapes mature with excessive amounts of malic acid which causes taste imbalance... 

Protein Stabilization. All grapes have a certain natural protein content of proteins both sensitive and insensitive to heat. The quantity of heat-sensitive protein varies with the vintage, cultivar, grape maturity, and pH. In the North Coast, Sauvignon blanc and Muscat cultivars have consistently high levels of heat-sensitive proteins. 

The same chemical principles presented by the speakers on red (p. 59) and white table wine (p. 29) production are applicable to table wine production in the Interior Valley. Differences in the size of the winery operations and grape maturity are attributable to regional climatic conditions. With modern viticultural practices, the grapes grown for winemaking in this interior region now produce quality wines and they also comprise the largest volume of table wines produced in California. 

Murphey, J.M., Spayd, S.E., Rowers, J.R. (1989). Effect of grape maturation on soluble protein characteristics of Gewiitziraminer and White Riesling juice and wine. Am. J. Enol. Vitic., 40, 199-207... 

Marais, J. (1987). Terpene concentration and wine quahty of Vitis vinifera L. cv Gewiirtraminer as affected by grape maturity and cellar practices. Vitis, 26, 231-245. 

Houtman, A. C., Morais, J., Du Plessis, C. S. (1980) Factors affecting the reproducibflity of fermentation of grape juice and of the aroma composition of wines. I Grape maturity, sugar, inoculation concentration, aeration, juice turbidity and ergosterol. Vitis, 19, 37-54. 

Jordao, A.M., Ricardo da Silva, J.M. and Laureano, O. (2001) Evolution of catechins and oligomeric procyanidins during grape maturation of Castelao Frances and Touriga Francesa, Am. J. Enol. Vitic., 52(3), 230-234. 

Monteiro, S., Pi arra-Pereira, M.A., Loureiro, V.B., Teixeira, A.R. and Ferreira, R.B. (2007) The diversity of pathogenesis-related proteins decreases during grape maturation, Phytochemistry, 68, 416-425. 

Hashizume, K. and Samuta, T. (1999). Grape maturity and light exposure affect berry methoxypyrazine concentration, Am. J. Enol. Vide., 50(2), 194-198. 

In the last 60 years perhaps too much emphasis has been placed on the methyl anthranilate content of labrusca grapes. For example measurements of this compound have been used to indicate grape maturity(H) it has been used as an indicator of the quality of grape products(12) and as a means of monitoring the performance of essence recovery equipment(H). Furthermore the amount of methyl anthranilate combined with the volatile ester content of grapes is presently being used to aid the grape breeders in their attempt to produce new cultivars with certain odor characteristics(liL). 

Fang, Y. Qian, M.C. (2006). Quantification of selected aroma-active compounds in Pinot noir wines from different grape maturities. Journal of Agricultural and Food Chemistry 54,8567-8573... 

As part of their metabolism, all yeasts are known to produce a wide range of esters such as ethyl acetate, isoamyl acetate, isobutyl acetate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and 2-phenylethyl acetate (Nykanen and Nykanen, 1977 Soles et al., 1982 Edwards et al., 1990 Webster et al., 1993 Rojas et al., 2001 2003 Plata et al., 2003 Lee et al., 2004). Esters are synthesized through reaction of alcohols (commonly, ethanol) and carboxylic acids by different acyltransferases or ester synthases (Mason and Dufour, 2000). Factors that affect ester synthesis include grape maturity, sugar content, fermentation temperature, and juice clarity (Houtman et al., 1980a 1980b Edwards etal., 1990). 

These preliminary observations directed subsequent research towards a more thorough study of maturation mechanisms. This chapter will cover the biochemical phenomena characterizing grape maturation and the process of the development of rot. It will also focus on the influence of environmental factors on maturation. 

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