Lemon and Lime - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 363

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Lemon and Lime

V. A. Jideani and I. A. Jideani

INTRODUCTION
Lemon ( Citrus limon (L.) Burm.) is a yellow or pale yel-
low fruit with 5-10 seeds. Botanically it is a berry, known
throughout the world, and is used in numerous food and
cuisines (Goodrich, 2003). Lemons and limes are acid
fruits. They are typically consumed in association with
other foods unlike other citrus varieties. Hence, they are
grown primarily for the fresh market with their juice as
flavoring in beverages. Generally, lemons are produced in
colder climates such as the western United States, Spain,
Italy, and Argentina. However, they can also adapt to dry
climates such as those found in Egypt, Iran, and India. Con-
versely, limes are highly sensitive to cold weather and are
grown exclusively in tropical climates; major producers are
Mexico and Brazil (FAO, 2003).
Lemons and limes, as we know them, are not dis-
tinguished by the Food and Agriculture Organization of
United Nations (FAO; 2010). Thus the data in Table 20.1
list top ten lemon and lime-producing, -exporting, and
-importing countries. India, Mexico, Argentina, China, and
Brazil were the major producers of lemon and lime in the
world. Spain, Mexico, Turkey, South Africa, and Argentina
were the major exporters, while the United States, the Rus-
sian Federation, the Netherlands, Germany, and France
were the major importers. In the African region, Egypt and
South Africa are the leading producers of lemon and lime
(Fig. 20.1).
The South African Summer Citrus growing region is lo-
cated in the southwestern part of the African continent, a
unique pristine part of South Africa with a Mediterranean
climate. Hot, dry summers and cold, wet winters form the

ideal environment for growing the finest summer citrus fruit
in the world (Summer Citrus, 2010). South Africa is the
best basket in the Southern Hemisphere for citrus produc-
tion: It has ethical and environmentally friendly reputation,
good climate for a diverse range, and low labor costs (Hu,
2010). The market for South African citrus is mainly Eu-
rope. The citrus industry being a highly competitive market
requires innovation, introduction of new varieties and new
products for producers and processors to stay competitive
in the global market. Newly introduced varieties of cit-
rus in the United States include 'Sonet' and 'Valley Gold'
(Hu, 2010).

LEMON AND LIME FRUIT STRUCTURE
The structure of lemon and lime fruit is similar to other cit-
rus fruits, which have received a special name: “hesperid-
ium” (Rieger, 2006). A hesperidium is a leathery rinded
berry consisting of the pericarp. Figure 20.2 details the sec-
tion of a lemon fruit showing the typical parts of citrus (hes-
peridium). The pericarp is made up of three distinct layers:
the exocarp (flavedo), which is the external colored layer or
peel, the mesocarp (albedo), the internal white layer of the
peel, and endocarp, which is the inner layer surrounding
the hollowed ovary and the containing seeds (Goodrich,
2003; Rieger, 2006; Guimaraes et al., 2010; Anon,

2010a).
Exocarp or flavedo is the outermost layer of the peri-
carp and forms the tough outer skin of the fruit, which
bears oil glands and pigments. Flavedo is mostly com-
posed of cellulosic material but also contains other compo-
nents, such as essential oils, paraffin waxes, steroids and