Soursop (also graviola, custard apple, and in Latin America, guanábana) is the fruit of Annona muricata, a broadleaf, flowering, evergreen tree. The exact origin is unknown; it is native to the tropical regions of the Americas and the Caribbean and is widely propagated. It is in the same genus, Annona, as cherimoya and is in the Annonaceae family.
The soursop is adapted to areas of high humidity and relatively warm winters; temperatures below 5 °C (41 °F) will cause damage to leaves and small branches, and temperatures below 3 °C (37 °F) can be fatal. The fruit becomes dry and is no longer good for concentrate.
With aroma similar to pineapple, the flavor of the fruit has been described as a combination of strawberries and apple, and sour citrus flavor notes, contrasting with an underlying creamy texture reminiscent of coconut or banana.
|Soursop fruit on its tree|
Annona muricata (common Spanish name: guanábana) is a species of the genus Annona of the custard apple tree family, Annonaceae, which has edible fruit. The fruit is usually called soursop due to its slightly acidic taste when ripe. Annona muricata is native to the Caribbean and Central America but is now widely cultivated – and in some areas, becoming invasive – in tropical and subtropical climates throughout the world.
Its young branches are hairy. Leaves are oblong to oval, 8 centimetres (3.1 in) to 16 centimetres (6.3 in) long and 3 centimetres (1.2 in) to 7 centimetres (2.8 in) wide. They are a glossy dark green with no hairs above, and paler and minutely hairy to no hairs below. The leaf stalks are 4 millimetres (0.16 in) to 13 millimetres (0.51 in) long and without hairs.
Flower stalks (peduncles) are 2 millimetres (0.079 in) to 5 millimetres (0.20 in) long and woody. They appear opposite from the leaves or as an extra from near the leaf stalk, each with one or two flowers, occasionally a third. Stalks for the individual flowers (pedicels) are stout and woody, minutely hairy to hairless and 15 millimetres (0.59 in) to 20 millimetres (0.79 in) with small bractlets nearer to the base which are densely hairy.
The petals are thick and yellowish. Outer petals meet at the edges without overlapping and are broadly ovate, 2.8 centimetres (1.1 in) to 3.3 centimetres (1.3 in) by 2.1 centimetres (0.83 in) to 2.5 centimetres (0.98 in), tapering to a point with a heart shaped base. They are evenly thick, and are covered with long, slender, soft hairs externally and matted finely with soft hairs within. Inner petals are oval shaped and overlap. They measure roughly 2.5 centimetres (0.98 in) to 2.8 centimetres (1.1 in) by 2 centimetres (0.79 in), and are sharply angled and tapering at the base. Margins are comparatively thin, with fine matted soft hairs on both sides. The receptacle is conical and hairy. The stamens are 4.5 millimetres (0.18 in) long and narrowly wedge-shaped. The connective-tip terminate abruptly and anther hollows are unequal. Sepals are quite thick and do not overlap. Carpels are linear and basally growing from one base. The ovaries are covered with dense reddish brown hairs, 1-ovuled, style short and stigma truncate.
The average weight of 1000 fresh seeds is 470 grams (17 oz) and they have an average oil content of 24%. When dried for 3 days at 60 °C (140 °F), the average seed weight was 322 grams (11.4 oz). They are tolerant of the moisture extraction, showing no problems for long-term storage under reasonable conditions.
Annona muricata is tolerant of poor soil and prefers lowland areas between the altitudes of 0 metres (0 ft) to 1,200 metres (3,900 ft). It cannot stand frost. The exact origin is unknown; it is native to the tropical regions of the Americas and is widely propagated. It is an introduced species on all temperate continents, especially in subtropical regions.
The plant is grown for its 20–30 cm (7.9–11.8 in) long, prickly, green fruit, which can have a mass of up to 6.8 kg (15 lb), making it probably the second biggest annona after the junglesop. Away from its native area, some limited production occurs as far north as southern Florida within USDA Zone 10; however, these are mostly garden plantings for local consumption. It is also grown in parts of Southeast Asia and is abundant on the Island of Mauritius.
The flesh of the fruit consists of an edible, white pulp, some fiber, and a core of indigestible black seeds. The pulp is also used to make fruit nectar, smoothies, fruit juice drinks, as well as candies, sorbets, and ice cream flavorings.
Due to the fruit's widespread cultivation and popularity in parts of Latin America, the Caribbean, Africa, Southeast Asia and the Pacific, soursop and its derivative products are consumed across the world, also via branded food and beverage products available in many countries, including Brazil, Mexico, Canada, the United States, the UK, Ireland and Continental Europe, Indonesia, Japan, Malaysia, Singapore and Vietnam.
In Mexico, Colombia, Venezuela, and Harar (Ethiopia), it is a common fruit, often used for dessert as the only ingredient, or as an agua fresca beverage; in Colombia and Venezuela, it is a fruit for juices, mixed with milk. In Cuba, a thick smoothie made of soursop pulp, milk and cane sugar goes by the name of champola. Ice cream and fruit bars made of soursop are common. The seeds are normally left in the preparation, and removed while consuming, unless a blender is used for processing.
In Indonesia, dodol sirsak, a sweetmeat, is made by boiling soursop pulp in water and adding sugar until the mixture hardens. Soursop is also a common ingredient for making fresh fruit juices that are sold by street food vendors. In the Philippines, it is called guyabano, derived from the Spanish guanábana, and is eaten ripe, or used to make juices, smoothies, or ice cream. Sometimes, they use the leaf in tenderizing meat. In Vietnam, this fruit is called mãng cầu Xiêm (Siamese Soursop) in the south, or mãng cầu (Soursop) in the north, and is used to make smoothies, or eaten as is. In Cambodia, this fruit is called tearb barung, literally "western custard-apple fruit." In Malaysia, it is known in Malay as durian belanda and in East Malaysia, specifically among the Dusun people of Sabah, it is locally known as lampun. Popularly, it is eaten raw when it ripens, or used as one of the ingredients in Ais Kacang or Ais Batu Campur. Usually the fruits are taken from the tree when they mature and left to ripen in a dark corner, whereafter they will be eaten when they are fully ripe. It has a white flower with a very pleasing scent, especially in the morning. While for people in Brunei Darussalam this fruit is popularly known as "Durian Salat", widely available and easily planted.
The fruit contains significant amounts of vitamin C, vitamin B1 and vitamin B2. The compound annonacin, which is contained in the seeds of soursop, is a neurotoxin identified in preliminary research.
|Nutritional value per 100 g (3.5 oz)|
|Energy||276 kJ (66 kcal)|
|Dietary fiber||3.3 g|
|Pantothenic acid (B5)||
|†Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
The Memorial Sloan-Kettering Cancer Center cautions, "alkaloids extracted from graviola may cause neuronal dysfunction". The compound annonacin, which is contained in the fruit and seeds of soursop, is a potent neurotoxin associated with neurodegenerative disease, and research has suggested a connection between consumption of soursop and atypical forms of Parkinson's disease due to high concentrations of annonacin. The LD50 of annonacin to dopaminergic neurons is 0.018 uM, which when compared to other known neurotoxins is 100-fold more toxic than 1-methyl-4-phenylpyridinium (MPP), 700 fold more than coreximine, and twice rotenone. Average fruit contains 15 mg of annonacin.
In 2010, the French food safety agency, Agence française de sécurité sanitaire des produits de santé, concluded that "it is not possible to confirm that the observed cases of atypical Parkinson syndrome ... are linked to the consumption of Annona muricata," calling for further study on potential risks to human health.
The Memorial Sloan-Kettering Cancer Center lists cancer treatment as one of the "purported uses" of soursop. According to Cancer Research UK, "Many sites on the internet advertise and promote graviola capsules as a cancer cure, but none of them are supported by any reputable scientific cancer organisations" and "there is no evidence to show that graviola works as a cure for cancer" and consequently they do not support its use as a treatment for cancer.
The Federal Trade Commission in the United States determined that there was "no credible scientific evidence" that the extract of soursop sold by Bioque Technologies "can prevent, cure, or treat cancer of any kind."
Cancer Research UK also released a statement about the alleged cancer "cure" that included these sentences: "Overall, there is no evidence to show that graviola works as a cure for cancer. In laboratory studies, graviola extracts can kill some types of liver and breast cancer cells that are resistant to particular chemotherapy drugs. But there haven’t been any large scale studies in humans. So we don't know yet whether it can work as a cancer treatment or not. Many sites on the internet advertise and promote graviola capsules as a cancer cure, but none of them are supported by any reputable scientific cancer organisations. We do not support the use of graviola to treat cancer."
In 2008, a court case relating to the sale in the UK of Triamazon, a soursop product, resulted in the criminal conviction of a man under the terms of the UK Cancer Act for offering to treat people for cancer. A spokesman for the council that instigated the action stated, "it is as important now as it ever was that people are protected from those peddling unproven products with spurious claims as to their effects."