The subsurface chemistry of the mangosteen exocarp comprises an array of polyphenolic acids including xanthones and tannins that assure astringency to discourage infestation by insects, fungi, plant viruses, bacteria and animal predation while the fruit is immature. Color changes and softening of the exocarp are natural processes of ripening that indicates the fruit can be eaten and the seeds are finished developing.
Mangosteen produces a recalcitrant seed and must be kept moist to remain viable until germination. Mangosteen seeds are nucellar in origin and not the result of fertilization; they germinate as soon as they are removed from the fruit and die quickly if allowed to dry.
Once the developing mangosteen fruit has stopped expanding, chlorophyll synthesis slows as the next color phase begins. Initially streaked with red, the exocarp pigmentation transitions from green to red to dark purple, indicating a final ripening stage. This entire process takes place over a period of ten days as the edible quality of the fruit peaks.
The edible endocarp of the mangosteen is botanically defined as an aril with the same shape and size as a tangerine 4–6 centimeters in diameter, but is white. The circle of wedge-shaped arils contains 4–8 segments, the larger ones harboring apomictic seeds that are unpalatable unless roasted.
Often described as a subtle delicacy, the arils bear an exceptionally mild aroma, quantitatively having about 400 times fewer chemical constituents than fragrant fruits, explaining its relative mildness. Main volatile components having caramel, grass and butter notes as part of the mangosteen fragrance are hexyl acetate, hexenol and α-copaene.
On the bottom of the exocarp, raised ridges (remnants of the stigma), arranged like spokes of a wheel, correspond to the number of aril sections. Mangosteens reach fruit-bearing in as little as 5–6 years, but more typically require 8–10 years.
The aril is the flavorful part of the fruit but, when analyzed specifically for its nutrient content, the mangosteen aril only meets the first criterion above, as its overall nutrient profile is absent of important content, it contains no pigmentation (correspondingly, no antioxidant phytochemicals in significant concentration) and there is no scientific evidence of aril constituents having any health properties.
Some mangosteen juice products contain whole fruit purée or polyphenols extracted from the inedible exocarp (rind) as a formulation strategy to add phytochemical value. The resulting juice has purple color and astringency derived from exocarp pigments, including xanthones under study for potential anti-disease effects. However, as xanthone research is at an early stage of basic laboratory research and only preliminary evidence has been found for anti-disease activity, no conclusions about possible health benefits for humans are warranted presently.
Furthermore, a possible adverse effect may occur from chronic consumption of mangosteen juice containing xanthones. A 2008 medical case report described a patient with severe acidosis possibly attributable to a year of daily use (to lose weight, dose not described) of mangosteen juice infused with xanthones. The authors proposed that chronic exposure to alpha-mangostin, a xanthone, could be toxic to mitochondrial function, leading to impairment of cellular respiration and production of lactic acidosis.
There is a legend about Queen Victoria offering a reward to anyone who could deliver to her the fabled fruit. In his publication, "Hortus Veitchii", James Herbert Veitch says that he visited Java in 1892, "to eat the Mangosteen. It is necessary to eat the Mangosteen grown within three or four degrees of latitude of the equator to realize at all the attractive and curious properties of this fruit."
An ultra-tropical tree, the mangosteen must be grown in consistently warm conditions, as exposure to temperatures below 40°F (4°C) will generally kill a mature plant.
Due to ongoing restrictions on imports, mangosteen is not commonly available to the public. Following export from its natural growing regions in Southeast Asia, the fresh fruit is available seasonally in some local markets like those of Chinatowns and rarely in produce sections of grocery stores in North America and Europe. Mangosteen and its related products, such as juices and nutritional supplements, are legally imported into the United States which had an import ban until 2007.
Mangosteens are readily available canned and frozen in Western countries. Without fumigation or irradiation as fresh fruit, mangosteens have historically been illegal for importation in commercial volumes into the United States due to fears that they harbor the Asian fruit fly which would endanger U.S. crops. This situation, however, officially changed on July 23, 2007 when irradiated imports from Thailand were allowed upon USDA approval of irradiation, packing and shipping techniques. Freeze-dried and dehydrated mangosteen arils can also be found.
From 2006 to present, private small volume orders from fruits grown on Puerto Rico are being filled for American gourmet restaurants who serve the aril pieces as a delicacy dessert. Beginning in 2007 for the first time, fresh mangosteens are also being sold for as high as $45 per pound from specialty produce stores in New York City.
Before ripening, the mangosteen shell is fibrous and firm, but becomes soft and easy to pry open when the fruit ripens. To open a mangosteen, the shell is usually scored first with a knife; one holds the fruit in both hands, prying gently along the score with the thumbs until the rind cracks. It is then easy to pull the halves apart along the crack and remove the fruit. Rarely in ripe fruits, the purple exocarp juice may stain skin or fabric.