Lemon and Lime - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 381

glycosylated flavanones; both are unique to citrus and are
thought to have bioactive properties such as anticancer,
anti-inflammatory, and antiviral effects, among others.
Methanol extracts of lemon seeds are rich in eriocitrin and
hesperidin, while peel extracts contain significant amounts
of neoeriocitrin, naringin, and neohesperidin (Gorinstein
et al., 2001; Jaganath and Crozier, 2009).
All fruits and fruit products contain a range of volatile,
low-molecular-weight ( < 250) compounds that are impor-
tant in producing the characteristic flavor and aroma of the
specific fruit. The predominant compounds responsible for
lemon aroma are relatively few (two to five) compared to
other citrus. The most important component is citral, an
aldehyde that is a cis-trans mixture of the isomers neral
and geranial. Volatile compounds identified in lemon oils
and essences are acetone myrcene, ethanol octanal, geranyl
acetate b-pinene, linalool a-terpineol, 3-buten-2-ol neral,
geranial octanol, limonene terpinene-4-ol, and methanol
(Goodrich, 2003).

Lemon and lime contain essential oils which have been
widely used for bactericidal, virucidal, fungicidal, antipar-
asitical, insecticidal, medicinal, and cosmetic applications,
especially in pharmaceutical, sanitary, cosmetic, and agri-
cultural, and food industries. In the food industries, essen-
tial oils are used as food preserves and flavor additives
(Burt, 2004). Essential oils contain a variety of volatile
molecules such as terpene and terpenoids (a terpene con-
taining oxygen), phenol-derived aromatic components, and
aliphatic components, all characterized by low molecular
weight. Some of these have antioxidant properties, suggest-
ing that beneficial effects of essential oils may be due to
pro-oxidant effects at cellular level (Bakkali et al., 2008).
It is now known that the pro-oxidant properties of these
compounds can play a significant protective role by re-
moving damaged cells by apoptosis (Bakkali et al., 2006;
Vukovic-Gacic et al., 2006).

Medicinal uses
Lemon juice is widely known as a diuretic, antiscorbutic,
and astringent. The sweetened juice is given to relieve gin-
givitis, stomatitis and inflammation of the tongue in Italy.
Lemon juice in hot water has been widely used as a daily
laxative and preventive of the common cold, but daily doses
have been found to erode the enamel of the teeth; prolonged
use will reduce the teeth to the level of the gums. Lemon
juice and honey or lemon juice with salt or ginger is taken as
cold remedy. Oil expressed from lemon seeds is employed
as medicine. The root decoction is taken as a treatment for
fever in Cuba and for gonorrhea in West Africa. An infu-
sion of the bark or of the peel of the fruit is given to relieve
colic (Morton, 1987a).
Limes are good for the relief of arthritis because they
have such a high vitamin C content and are especially good
for anyone with acidemia because they are one of the most
alkalinizing foods. A drink of lime juice and whey is a
wonderful cooler for the brain and nervous system (Anon,
2010b).
The sweet lime is valued in India because of its therapeu-
tic cooling effect in cases of fever and jaundice. In Malaysia,
the juice is taken as a tonic to relieve stomach ailments. In
India, the pickled fruit is eaten to relieve indigestion. The
juice of the Mexican lime is regarded as an antiseptic, tonic,
an astringent, and as a diuretic in liver ailments, a digestive
stimulant, a remedy for intestinal hemorrhage and hem-
orrhoids, heart palpitations, headache, convulsive cough,
rheumatism, arthritis, falling hair, bad breath, and as a dis-
infectant for all kinds of ulcers when applied in a poultice
(Morton, 1987b).

Health-beneficial compounds
Lemon has been categorized as the third most important
citrus species because it is an important health-promoting
fruit rich in phenolics compounds, vitamins, minerals, di-
etary fiber, essential oils, and carotenoids. An excellent
review on the phytochemistry, analytical aspects of lemon
compounds, importance for food industry, relevance for nu-
trition and health, and bioactive compounds of Citrus limon
was published recently (Gonzalez-Molina et al., 2010).
Lemon has demonstrated activity in the control of various
health conditions like cancer, cardiovascular and coronary
heart diseases (CVD and CHD), oxidative damage and lipid
metabolic disorder, obesity, and other diseases. The natural
bioactive compounds in lemon and lime are of benefit in
food and health.
Lemon and lime juices contain a wide range of pheno-
lic compounds, including flavanones with antioxidant ca-
pabilities that could have health benefits (Leonard et al.,
2002; Proteggente et al., 2002; Peterson et al., 2006; Xu
et al., 2008; Kuljarachanan et al., 2009) as well as hy-
drophilic phytochemicals (Konczak et al., 2010). The tar-
geting of excessive free radicals with peels and juices of
lemon, lime, and other citrus fruits has been demonstrated
by Guimaraes et al. (2010). Drinks rich in healthy bioactives
have been developed combining lemon and pomegranate
juices (Gonzalez-Molina et al., 2009). Beneficial uses of
lemon and lime have found use as source of flavonoids of
pharmaceutical interest (del Rıo et al., 2004). Other exam-
ples are the use of hill lemon in making functional drinks
with basil ( Ocimum sanctum ).