Dates - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 171

10
Dates

Salah M. Aleid

INTRODUCTION
Date palms ( Phoenix dactylifera L.) grow in hot, arid re-
gions of the world, and the fruit is marketed worldwide as
a high-value sweet fruit crop. Dates are considered an im-
portant subsistence crop in most of the world's desert areas
(Al-Shahib and Marshall, 2003). The date palm has traveled
remarkably well as civilization moved out of the Middle
East and reached places such as Spain and the United States,
with the Coachella Valley in California being the primary
commercial region of date production in the United States
(Sauer, 1993). The world total number of date palms is
about 100 million, distributed in 34 countries (Zaid, 2006).
The world production of dates has increased about threefold
over past 4 decades. The Arab states produce about 73%
of global production. According to the Food and Agricul-
ture Organization (FAO), 7.91 million metric tons of dates
were produced in 2010 with the main tonnage coming from
Egypt (17.1%), followed by Saudi Arabia (13.6%), Iran
(12.9%), United Arab Emirates (10.4%), with Pakistan,
Algeria, Iraq, Sudan, Oman, Libya, China, and Tunisia be-
ing the other major producers (Table 10.1). United Arab
Emirates, Iraq, Pakistan, Tunisia, and Iran were the leading
dates exporters in 2009, while India, United Arab Emirates,
Morocco, France, and Yemen were the major importers
(Table 10.1).
Depending on their water content, dates are classified
as soft, semidry, and dry. Fresh dates are typically found
on the market as partially ripe fruit, as fully ripe fruit
being prone to rapid decay, which cannot be transported
over longer distances, and finally as dried dates which
may be good for 1 year at appropriate storage conditions

(Liebster and Levin, 1999). Dates are on the borderline
between dried fruit and fresh fruit. They are a dried fruit
because they have a moisture reduced by natural or arti-
ficial drying and thus fairly long keeping potential. They
are fresh fruit because they are kept optimally only in a
chilled atmosphere to avoid fermenting activities and be-
coming unsuitable for consumption. Natural or fresh dates
are generally harvested, branched, and packed without any
processing or may be frozen as soon as they are harvested
(Barreveld, 1993).
Despite the importance and broad areas of date palm cul-
tivation, field and postharvest losses are high, and methods
for measuring product quality and use of date products and
by-products need improvement. To address these issues,
most producing countries in central and West Asia and
North Africa have ranked date palm as a high-research-
priority crop (Mahmoudi et al., 2008).

MATURITY STAGES
Date fruits pass through several distinct stages of matu-
rity, typically described by changes in color, texture, and
taste/flavor. The difference in these stages has been at-
tributed to changes in chemical composition, mainly sugars
and tannins (Myhara et al., 1999). Fruit maturation under-
goes four major stages, as shown in Fig. 10.1, identified in
the date industry by their Arabic names, as follows.

Kimri stage
The first stage is called Kimri, approximately 19 weeks
after pollination, when the fruit appears as small and
green, with a hard texture, and is nonedible. This stage is