Guava - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 208

season, maturity stage, and variety. Similar to most other
fruits, guava has low fat and protein and high water content.
However, their ash and fiber contents are considered high
as compared to other fruits.
Carbohydrates are the main nonaqueous component of
guava, and their composition also depends on the guava
variety. Of the total carbohydrates content, about 60% are
sugars, with a predominance of fructose (about 59%), fol-
lowed by 35% glucose and 5% sucrose (Yusof, 2003).
Guavas are an excellent source of essential minerals such
as calcium, phosphorus, magnesium, and iron. They are
also a good source of many vitamins like niacin, thiamine,
riboflavin, and

However, the association of OD using a sucrose solution
as a pretreatment to convective drying (60 ◦ C, 3-4 hours)
allowed for the production of products with a higher re-
tention of ascorbic acid and carotenoids than the nondehy-
drated fruits (Sanjinez-Argando na et al., 2005), which was
attributed to a sugar barrier layer formed on the surface of
the fruit. In addition, it was observed that thermal process-
ing may be responsible for rupture of the fruit membranes,
releasing lycopene from red guava, enhancing its bioavail-
ability, and intensifying the red color of the processed fruits
(Sato et al., 2006).

β

-carotene, besides being an exceptional
source of vitamin C, presenting up to four times the amount
found in oranges (US Department of Agriculture, 2009).
Moreover, guavas are also a good source of natural antiox-
idants such as the polyphenols and carotenoids (Alothman
et al., 2009). Polyphenol compounds are found in the peel
(7.79%) and pulp (2.62%), contributing significantly to the
high antioxidant capacity of guava (Jimenez-Escrig et al.,
2001). The red species of guava contains between 44.8
and 61.0 μg/g of total carotenoids, of which 76-86% is
lycopene, characterizing this fruit as a rich source of this
carotenoid (Padula and Rodriguez-Amaya, 1986). Interest
in the study of this compound, responsible for the redness
in tomato, watermelon, and guava, has grown in recent
years due to its possible role in the prevention of oxidative
stress and degenerative diseases such as cancer and cardio-
vascular diseases (Rissanen et al., 2002; Rao et al., 2006;
Riccioni et al., 2008; Kong et al., 2010).

Medicinal properties
Some regions, such as Mexico and other Latin American
countries, Africa, and Asia, have a long history of tradition-
ally using guava for medicinal purposes (Gutierrez et al.,
2008). In addition to the fruit, the guava roots, shoots, bark,
leaves, and flowers are traditionally known to show innu-
merous medicinal properties. Of these, the most traditional
uses include the treatment of gastrointestinal diseases such
as diarrhea, dysentery, digestive problems, ulcers, gastric
insufficiency, and cholera. They may also be used for treat-
ing a number of respiratory diseases such as colds, coughs,
respiratory disturbances, laryngitis, and sore throats, be-
sides being used topically for treating skin ulcers, wounds,
and other skin problems. Other reported uses of guava tree
parts are in the treatment of hypoglycemia, fever, dehy-
dration, rheumatism, diabetes mellitus, and hypertension
(Almeida et al., 1995; Tona et al., 1998; Leonti et al., 2001;
Lewu and Afolayan, 2009; Andrade-Cetto, 2009).
In recent years, guava leaves have received particular at-
tention mainly for containing a large number of compounds
such as essential oils rich in cineol, tannins, flavonoids, and
triterpenes. They have been the subject of numerous re-
search projects to identify their pharmacological activities,
which have confirmed the potential of this plant in exhibit-
ing antioxidant, antiallergy, hepatoprotective, antimicro-
bial, antigenotoxic, cytotoxic, antispasmodic, anticough,
antidiabetic, and antiinflamatory activities (Qian and Ni-
horimbere, 2004; Seo et al., 2005; Bartolome et al., 2006;
Belemtougri et al., 2006; Abubakar, 2009; Deguchi and
Miyazaki, 2010; Isabelle et al., 2010; Kong et al., 2010).

Effect of processing on nutrients
Most guava products are subjected to heat treatment during
processing, either as a processing step (e.g., concentration)
or to ensure their microbiological safety. However, the high
temperatures usually degrade vitamins and other nutritional
components. Moreover, the presence of oxygen may lead to
oxidation of vitamins and minerals, further reducing the nu-
tritional value. Generally, vitamin C oxidation is catalyzed
by metallic ions and by the high temperatures of processing
and storage (room temperature) in tropical and subtropical
countries (Martin and Kato, 1988).
The stability of vitamin C and the carotenoid contents
were evaluated during the processing and storage of guava
nectar heat treated at 90 ◦ C for 1 min (Silva et al., 2010);
these authors obtained a product with considerably lower
values of these compounds after processing, reaching up
80% of losses. Storage for 250 days reduced the ascorbic
acid content by

REFERENCES
Abd El-Aal MH. 1992. Production of guava seed protein iso-
lates: Yield, composition and protein quality. Food/Nahrung
36: 50-55.
Abubakar EMM. 2009. The use of Psidium guajava Linn.
in treating wound, skin and soft tissue infections. Sci Res
Essays 4: 605-11.

35% but did not influence on the total
carotenoids (Silva et al., 2010).

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