Grape drying

Depending on the production rules and the local traditions, different techniques are used to remove the water from the grapes that are used for the production of passito wines (see above Table 3.2). 

Accordingly, the techniques applied for grape drying are still based on empirical practices, and often the controls applied consist only in 

Regarding organic acids metabolism, Amati et al. (1983) reported that malic acid is consumed in both natural and conditioned systems, although it was more intense in the latter. This malic acid decrease is probably due to the respiration processes and /or to malic acid conversion into sugar (gluconeogenesis). In contrast, tartaric acid decreases slightly, and no differences were seen between the two drying systems. 

While most of the studies carried out to date have focused on the evolution of the primary compounds, such as the sugar and acid components, little data exist for the other quality characteristics, and in particular, for aroma. However, most of these studies have been conducted on the aromatic varieties. For instance, some experimental studies conducted on different aromatic cultivars under different conditions mainly reported the evolution of terpene compounds during the dehydration process. Accordingly, it has been showed that after the grape harvest, activation or inhibition of the metabolism involved in the biosynthesis of the aroma compounds is strictly dependent on the grape dehydration technique. 

A similar study carried out on Malvasia delle Lipari grapes (Corte et al. 2001) showed that in the relevant passiti wine the content of glycosylated terpenes was extremely high, particularly in a sample obtained from grapes dried in an artificial dehydration system the wine obtained from the use of this artificial dehydration showed a glycosylated terpene 

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Dimethipin. 2,3-Dihydro-5,6-dimethyl-l,4-dithiin-l,l,4,4-tetraoxide [55290-64-7] (dimethipin, oxidimetbiin, UBI-N252, Harvard) (25) is used as a cotton defoHant and has been used as an experimental desiccant in potato vines. In addition, it defoHates nursery stock, grapes, dry beans, and natural mbber and is used as a desiccant for seed of canola, flax (l lnum usitatlssimum), rice, and sunflower (He/lanthus annuus) (10). The product has been available since the mid-1970s and the experimental work was first reported in 1974 (44). 

This EU definition already highlights well the difference between Vin Santo produced in Italy and that produced on Santorini Island, Greece, which arise mainly from the different systems for the grape drying in Italy, in mild condition (aerated places), and in Greece, under the sun. 

As will be explained in more detail below, all Italian Vin Santo production traditionally follows the same basic scheme, although there are major differences in the grape varieties used and in the degree of grape drying these lead to the different types and styles of Vin Santo. 

TABLE 3.2 Main grape-drying systems for the production of passito wines... 

Influence of grape drying on microbial population dynamics in... 

FIGURE 9.3 A traditional grapes drying loft located in Mazzano (Valpolicella area). 

To perform a rapid grape drying and avoid water condensation overnight for grapes used in the vinification of dessert wines ... 

For any of the superfruits listed, try fig slices, red grapes, dried or fresh blueberries, red raspberries, dried blackcurrants, dried cranberries, date slices, or walnut pieces. 

Berberis. Holly-leaved barberry Oregon grape root mountain grape. Dried rhizome and roots of species of section of Mahonia DC. of the genus Berberis L., Berberida-ceae. Habit, U.S. and British Columbia. Constit, Berberine, berbemine, oxyacanthine, phytosterol, sugar. 

Good quality dried raisins (dried Thompson seedless grapes), dried flge and fresh figs (Callmyrna variety) were obtained from processors In the Fresno, California area and from local markets for comparison. Authentic chemical compounds for comparison were obtained from reliable commercial sources or synthesized by known methods. 

Vitis vinifera L. is a perennial woody vine belonging to the Vitaceae family. It is a productive plant, considered the world s premier fruit, occupying 7.6 million hectares of viticultural land in 2010. It is used mainly for wine (6.8 million hectares) but also for juice, fresh consumption (table grapes), dried fruit, and distilled liquor. 

The fruits which are most commonly dried in the United States are apples, apricots, dates, figs, nectarines, peaches, plums, prunes, and seedless grapes. Drying reduces the water content of the fruit to about 24%, which is usually low enough to prevent spoilage. Slow drying of fruits in the sun may result in the destruction of much of the vitamin A and... 

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