Table grape color

The term "table grape" is used to distinguish fruit that is destined to be eaten fresh rather than to be dried or made into wine. Of course, any ripe grape can be eaten fresh, but over the centuries there has been selection of varieties that were seedless on the one hand and that were larger berried, firmer fleshed and with more attractive colors on the other hand. Selection for attractive color has been paralleled by selection of large size. We find thus that quality attributes in table grapes can be considered from two categories, the visual and the palate. Visual factors of obvious importance to quality in table fruit are size, color, shape, and intact bloom on the berries. 

Table grapes—Aside from being a handy snack, table grapes also offer tantalizing color, flavor, and texture contrasts to all types of recipes. They can be enjoyed in a myriad of ways—in salads, pudding, pies, cakes, tarts, fruit cups, as meat accompaniments, condiments, and relishes, or just as is. 

Two classes of dimeric anthocyanins isolated from plants (section 10.2.6) have been identified in plants for the first time. One class includes pigments where an anthocyanin and a flavone or flavonol are linked to each end of a dicarboxylic acyl unit. The other class includes four different catechins linked covalently to pelargonidin 3-glucoside. During the last decade, seven new desoxyanthocyanidins and a novel type of anthocyanidin called P)Tanoanthocyanidins have been reported (Section 10.2.2). Toward the end of the 20th century, several color-stable 4-substituted anthocyanins, pyranoanthocyanins, were discovered in small amounts in red wine and grape pomace.Recently, similar compounds have been isolated from extracts of petals of Rosa hybrida cv. M me Violet, scales of red onion, and strawberries. About 94% of the new anthocyanins in the period of this review are based on only six anthocyanidins (Table 10.2). 

Anonymous, Color Breakdown of Shipments of Bottled California Grape Table... 

It is thus possible to calculate the percentage of the various forms of anthocyanins according to pH (Figure 6.19), especially in wine with a pH between 3 and 4 (Table 6.1). The proportion of strongly colored forms is higher in mixed grape anthocyanins than in malvine alone (Table 6.2). 

Table 6.2. Comparison of the percentage color at 520 nm, between pH 3 and pH 4, calculated for a grape anthocyanin solution and a malvidin monogluco-side solution. (Glories, 1984)...

This notion of anthocyanin extractability depends on the state of maturity that controls the breakdown of skin cells (Table 6.15). All other conditions being equal, when grapes are perfectly ripe or slightly overripe, the anthocyanin content in the wine is higher than it would have been prior to maturity, although these pigments tend to decrease in grapes. Both color and total phenol content are at a maximum. 

Phenolic compounds. The anthocyanlns and tannins are particularly Important constituents of wine grapes in that they provide the attractive color to red wines and the desirable bitterness and astrlngency associated with the table wines. While the concentrations and types of anthocyanlns present in the various cultivars and species differ, most red wine grapes contain enough of these compounds in the skins so that satisfactory colors are produced during the fermentation of the wine when the... 

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