Guava is a genus of about 100 species of tropical shrubs and small trees in the myrtle family Myrtaceae. Native to Mexico and Central America, northern South America, parts of the Caribbean and some parts of North Africa, it is now cultivated throughout the tropics. Numerous references in medical research identify guava as Psidium guajava.
In several tropical regions, including Hawaii, some species (namely Cattley guava a.k.a. strawberry guava, P. littorale) have become invasive weed shrubs. On the other hand, several species have become very rare and at least one (Jamaican guava, P. dumetorum), is already extinct.
Mature trees of most species are fairly cold-hardy and can survive as low as 5°C for short periods of time, but younger plants will not survive. They are known to survive in Northern Pakistan where they can get down to 5°C or lower during the night. Guavas are also of interest to home growers in temperate areas, being one of the very few tropical fruits that can be grown to fruiting size in pots indoors.
The whole fruit is edible, from seeds to rind, but many people choose to cut out the middle hard seeds embedded in surrounding pulp. The pulp is sweetest near the center, with outer layers being sour and gritty like young pears, while the peel is sour in taste but richest in phytochemicals; it is usually discarded but can be eaten as an enriched source of polyphenols and essential nutrients, especially an exceptional content of dietary fiber.
The fruit is also often prepared as a dessert. In Asia, fresh raw guava is often dipped in preserved prune powder or salt. Boiled guava is also extensively used to make candies, preserves, jellies, jams, marmalades (goiabada), juices and aguas frescas. In Asia, a tea is made from guava fruits and leaves. Guava juice is very popular in Mexico, Egypt and South Africa. Red guavas can be used as the base of salted products such as sauces, constituting a substitute for tomatoes, especially for those sensitive to the latter's acidity.
Guava wood is used for meat smoking in Hawaii and competition barbecue.
Psidium species are used as food plants by the caterpillars of some Lepidoptera, mainly moths like the Ello Sphinx (Erinnyis ello), Eupseudosoma aberrans, Snowy Eupseudosoma (E. involutum)and Hypercompe icasia. Mites like Pronematus pruni and Tydeus munsteri are known to parasitize Apple Guava (P. guabaya) and perhaps other species. The bacterium Erwinia psidii causes rot diseases of the Apple Guava.
Guavas are often considered superfruits, being rich in vitamins A and C, omega-3 and -6 polyunsaturated fatty acids (mainly in the seeds which must be chewed to obtain the omega fats) and especially high levels of dietary fiber. A single guava contains over four times the amount of vitamin C as a single orange (228 mg per 100 g serving), and also has good levels of the dietary minerals, potassium, magnesium, and an otherwise broad, low-calorie profile of essential nutrients.
However, nutritional value is greatly dependent on species, the strawberry guava notably containing only 37 mg of vitamin C per 100g serving, practically a tenth of the vitamin C found in more common varieties. Vitamin C content in strawberry guava, however, is still a high percentage (62%) of the Dietary Reference Intake for this vitamin.
Guavas contain both major classes of antioxidant pigments -- carotenoids and polyphenols, giving them relatively high dietary antioxidant value among plant foods. As pigments provide plant food their colors, guavas that are red, yellow or orange in color have more potential value as antioxidants sources than unpigmented species.
|Food Value Per 100 g of Edible Portion|
|Dietary Fiber||2.8-5.5 g|
|Carotene (Vitamin A)||200-400 I.U|
|Vitamin C (variable by species)||37-400 mg|
Nutrient data source: US Department of Agriculture from Healthaliciousness.com
Since the 1950s, guava, particularly its leaves, has been a subject for diverse research in chemical identity of its constituents, pharmacological properties and history in folk medicine. For example, from preliminary medical research in laboratory models, extracts from guava leaves or bark are implicated in therapeutic mechanisms against cancer, bacterial infections, inflammation and pain. Essential oils from guava leaves have shown strong anti-cancer activity in vitro.