Agriculture Reference
In-Depth Information
9
Grapes
Christian Chervin, Julia Aked and Carlos H. Crisosto
INTRODUCTION, BOTANY, CULTIVATION
AND PRODUCT STATISTICS
further reading on this topic. There is relatively little
published on the specific post-harvest requirements for
grapes used for drying. In the section entitled 'Post-harvest
technology for dried grapes', a summary of the basic
processing and product preservation is provided.
Introduction
The grape was one of the first fruits to be cultivated by man.
Since the dawn of civilisation, the fermented product of
grapes, wine, has probably been an important way of con-
suming grapes (McGovern
et al
. 1995). Wine residues have
been identified in 7000-year-old jars in Iran (McGovern
et al
.
1996). However, consumption of the fresh and dried fruit has
probably always been popular where the vines grew wild.
This chapter provides some basic information about the
cultivation of grapes (this section) before looking at the
physiology and biochemistry of the developing and mature
grape berry. The final three sections of the chapter deal
with post-harvest aspects of grapes pertaining to the three
main product types: beverages (wine and juice), fresh fruit
(table grapes) and dried fruit (sultanas, raisins and
currants). Although today most grapes are converted to
wine, the development of the post-harvest technology for
grapes has concentrated on the fresh fruit. This is because
all the eating-quality parameters (appearance, texture and
taste) must be high in the commercial product. The quality
of grapes for wine, drying or for other grape products is
primarily dependent on harvesting the right varieties at the
right time and preventing unwanted chemical changes
during processing. The topic of wine production is so huge
that this chapter describes only the quality factors required
in the harvested grape as the basis of a good wine. Details
of processing are omitted but references are given for
Botany
The grape plant is a vigorous vine of the family Vitidaceae
Juss. (syn. Ampelidaceae; Vitacae) (Watson & Dallwitz
1991, 1992). The European grape
Vitis vinifera
(L.) is
hermaphrodite whereas some native North American
Vitis
species are monoecious. Multiple buds are produced
laterally on the previous season's cane and flowers are
wind pollinated. The fruit clusters mature about 5-7
months after bud burst. The main cultivars in commercial
production are described in the product sections below.
Cultivation
Grape is one of the world's most widely grown fruit crops
in relatively warm temperate-zone climates (see product
statistics below). It is not well adapted to subtropical or
tropical areas although special management allows dessert
grapes to be harvested 2-4 times per year in tropical
countries such as Thailand and Indonesia. Heat accumula-
tion determines the type of grape that can be successfully
grown. Between 950°C day and 1500°C day wine
production predominates; above 1500°C day table grapes
and fortified wines can be produced and above 1950°C day
table grapes and dried fruit are dominant (Jackson &
Looney 1999).
