Grape white wine

Cajfeic acid White grapes, white wine, olives, spinach, cabbage, asparagus and, coffee Exerts antidepressive and anxiolytic-like effects through indirect modulation of the alpha lA-adrenoceptor system [46]... 

Wine. The earliest known wines were made in Iran about 5400—5000 BC (25). The species of grape used is unknown and may have been either the wild grape Fitis viniferus sylvestris or a cultivated precursor of the modem wine grape V. viniferus viniferus. The source of the yeast used, and the procedures used are completely unknown. In modem times, grapes (about 21—23% sugar) are pressed the liquid must is either separated and allowed to settle for 1—2 days (for white wines) before inoculation with yeast, or the whole mass is dkectly inoculated with yeast (for red wines). In either case, while the initial fermentation takes place, the carbon dioxide formed by fermentation excludes ak and prevents oxidation. White wines are transferred to a second fermentor (racked) near the end of fermentation and kept isolated from the ak while solids, including yeast, settle out, a process that requkes about six... 

The addition of exogenous glycosidases enhance greatly aromas in wines in relation with the aromatic potential of grape varieties. Tastings confirm that the improvement is obvious for red and for white wines. Wines are always judged more fruity and more intense. 

The complexity of wine composition is a central reason for the vast variety of wines in the marketplace. In addition to water and ethanol, the major components, a variety of organic acids as well as metal ions from minerals in the skin of the grape are present. Initially, all of these substances remain dissolved in the bottled grape juice. As the fermentation process occurs, the increasing alcohol concentration in the wine alters the solubility of particular combinations of acid and metal ions. Unable to remain in solution, the insoluble substances settle as crystals. Since the process of red-wine making involves extended contact of the grape juice with the skins of the grapes (where the minerals are concentrated), wine crystals are more common in red wines than in white wines. 

Figure 19 presents results of PCL examination of wines, grape skins, and grape pips. The very low antioxidant capacity of white wine is obviously related to the technology of its manufacturing it is prepared from pure juce without grape skins and pips, in contrast to red wine. The dependency of ACW on the storage time of red wine is depicted in Figure 20. White wine is stable in this sense.

Waters, E. J., Peng, Z., Pocock, K. F., and Williams, P. J. (1995). Proteins in white wine, I Procyanidin occurrence in soluble proteins and insoluble protein hazes and its relationship to protein instability. Aust. ]. Grape Wine Res. 1, 86-93. 

Flavonoids (sensu largo, i.e., including flavanoids) are important components of grapes and essential to wine quality. They are responsible for the color and astringency of red wines as well as for the yellow hue of oxidized white wines, and are also involved in the development of... 

White musts and wines made without maceration contain very low amounts of flavonoids. However, when making white wine from white grapes, skin contact at low temperature is sometimes performed before pressing and fermentation to increase extraction of volatile compounds and aroma precursors. After 4h of skin contact, the concentration of flavanol monomers and dimers in must was increased threefold. Delays between harvest and pressing, especially if sulfur dioxide is added to prevent oxidation, as well as thorough pressing, similarly result in increased concentrations of flavonoids in white musts and wines. " " ... 

The only known chemical differences between grape varieties concerns the red pigments grapes with or without anthocyanins or grapes with or without anthocyanins diglucosides. These differences form the basis for the methods of characterizing vine products white wines and... 

E Falque Lopez, E Fernandez Gomez. Simultaneous determination of the major organic acids, sugar, glycerol, and ethanol by HPLC in grape musts and white wines. J Chromatographic Sci 34(5) 254-257, 1996. 

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