Açaí palm

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Açaí palm
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
(unranked):	Commelinids
Order:	Arecales
Family:	Arecaceae
Genus:	Euterpe
Species:	E. oleracea
Binomial name
Euterpe oleracea Mart.

The açaí palm (Portuguese: [aˌsaˈi] ( listen)) (Euterpe oleracea) is a species of palm tree in the genus Euterpe cultivated for their fruit and superiorhearts of palm. Its name comes from the Portuguese adaptation of the Tupian word ïwaca'i, '[fruit that] cries or expels water'. Global demand for the fruit has expanded rapidly in recent years, and açaí is now cultivated for that purpose primarily. Euterpe edulis (juçara) is a closely related species which is now the primary source of hearts of palm. ^[1]

Eight species are native to Central and South America, from Belize southward to Brazil and Peru, growing mainly in swamps and floodplains. Açaí palms are tall, slender palms growing upwards of 25+ meters (82 feet), with pinnate leaves up to 3 meters (9.8 feet) long.^[2]

Cultivars

Few named cultivars exist, and varieties differ mostly in the nature of the fruit:

• 'Branco' is a rare variety local to the Amazon estuary in which the berries do not change color but remain green when ripe. This is believed to be due to a recessive gene since of 'Branco' palm seeds only about 30% mature to express this trait. It has less iron and antioxidants but more oil and many believe it to have a superior taste and digestability to purple açaí.^[9]
• 'BRS-Para Dwarf' was developed by the Brazilian Agricultural Research Agency. It grows to at most 5-7 meters tall, fruits sooner (3 years from seed), and produces a larger seed yielding 25% more fruit pulp than wild açaí.^[10]

[edit]Other uses

Apart from the use of its fruit as food or beverage, the açaí palm has other commercial uses. Leaves may be made into hats, mats, baskets, brooms and roof thatch for homes, and trunk wood, resistant to pests, for building construction.^[11] Tree trunks may be processed to yield minerals.^[12] The palm heart is widely exploited as a delicacy.^[13][14]

Comprising 80% of the fruit mass, açaí seeds may be ground for livestock food or as a component of organic soil for plants. Planted seeds are used for new palm tree stock, which, under the right growing conditions, can require months to form seedlings.^[15] The seeds are a source of polyunsaturatedand saturated fatty acids^[11][16][17]

[edit]Nutritional content

A powdered preparation of freeze-dried açaí fruit pulp and skin was reported to contain (per 100 g of dry powder) 533.9 calories, 52.2 gcarbohydrates, 8.1 g protein, and 32.5 g total fat. The carbohydrate portion included 44.2 g of dietary fiber and low sugar value (pulp is not sweet).^[17] The powder was also shown to contain (per 100 g): negligible vitamin C, 260 mg calcium, 4.4 mg iron, and 1002 U vitamin A, as well asaspartic acid and glutamic acid; the amino acid content was 7.59% of total dry weight (versus 8.1% protein).

The fat content of açaí consists of oleic acid (56.2% of total fats), palmitic acid (24.1%), and linoleic acid (12.5%).^[17] Açaí also contains beta-sitosterol (78–91% of total sterols).^[17][18] The oil compartments in açaí fruit contain polyphenols such as procyanidin oligomers and vanillic acid, syringic acid, p-hydroxybenzoic acid, protocatechuic acid, and ferulic acid, which were shown to degrade substantially during storage or exposure to heat.^[19]

[edit]Food product

In the general consumer market, açaí is sold as frozen pulp, juice, or an ingredient in various products from beverages, including grain alcohol, smoothies, foods, cosmetics and supplements.

[edit]Dietary supplement

See also: Enforcement actions against açaí berry supplement manufacturers

In 2004, it became popular to consume açaí as a supplement due in part to the rapid success of multi-level marketing company MonaVie that sells an açaí blend tonic for $40 a bottle. Another reason is the proliferation of various açaí supplement companies that misused celebrity names likeOprah Winfrey and Rachael Ray to promote açaí weight loss pills online.^[20]

Marketers of these products make unfounded claims that açaí and its antioxidant qualities provide a variety of health benefits, none of which has scientific confirmation to date. False claims include reversal of diabetes and other chronic illnesses, as well as expanding size of the penis and increasing men's sexual virility.^[21] As of April 2012, there are no scientifically controlled studies providing proof of any health benefits from consuming açaí. No açaí products have been evaluated by the FDA, and their efficacy is doubtful.^[22] Specifically, there is no scientific evidence that açaí consumption affects body weight, promotes weight loss or has any positive health effect.^[23]

According to the Washington, D.C. based Center for Science in the Public Interest (CSPI) thousands of consumers have had trouble stopping recurrent charges on their credit cards when they cancel free trials of açai-based products.^[24][25] Even some web sites purporting to warn about açai-related scams are themselves perpetrating scams.^[23]

In late 2008, lawyers for The Oprah Winfrey Show began investigating statements from supplement manufacturers who alleged that frequent Oprahguest Dr. Mehmet Oz had recommended their product or açai in general for weight loss.^[22]

One laboratory study found that commercially available açaí powder added to the diet of fruit flies lengthened their lives when challenged by chemical or genetic oxidative stress.^[26] Dietary açaí also restored the flies' circadian rhythm disturbed by the herbicide paraquat.

[edit]Polyphenols and antioxidant activity in vitro

A comparative analysis from in vitro studies reported that açaí has intermediate polyphenol content and antioxidant potency among 11 varieties of frozen juice pulps, scoring lower than acerola,mango, strawberry, and grapes.^[27]

A powdered preparation of freeze-dried açaí fruit pulp and skin was shown to contain cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside as major anthocyanins;^[28] (3.19 mg/g) however, anthocyanins accounted for only about 10% of the overall antioxidant capacity in vitro.^[29] The powdered preparation was also reported to contain twelve flavonoid-like compounds, includinghomoorientin, orientin, taxifolin deoxyhexose, isovitexin, scoparin, as well as proanthocyanidins (12.89 mg/g), and low levels of resveratrol (1.1 μg/g).^[17] A study on another different freeze-dried açaí product (Opti-Acai) reported that the formulation contained much lower levels of anthocyanins, proanthocyanadins, and other polyphenol compounds as compared with blueberries and other antioxidant-rich fruits.^[30]

In an in vitro study of different açaí varieties for their antioxidant capacity, a white one displayed no antioxidant activity against different oxygen radicals, whereas the purple variety most often used commercially had antioxidant activity against peroxyl radicals and to a lesser extent peroxynitrite but little activity against hydroxyl radicals.^[29]

Freeze-dried açaí powder was found to have antioxidant activity in vitro against superoxide and peroxyl radicals, and mild activity for peroxynitrite and hydroxyl radicals.^[30] The powder was reported to inhibit hydrogen peroxide-induced oxidation in neutrophils, and to have a slight stimulatory effect on the reactive radical, nitric oxide.^[31]

Extracts of açaí seeds were reported to have antioxidant capacity in vitro against peroxyl radicals, similar to the antioxidant capacity of the pulp, with higher antioxidant capacity against peroxynitrite and hydroxyl radicals.^[32]

The anthocyanins of fruit likely have relevance to antioxidant capacity only in the plant's natural defensive mechanisms^[33] and in vitro.^[34] The Linus Pauling Institute and European Food Safety Authority state that dietary anthocyanins and other flavonoids have little or no direct antioxidant food value following digestion.^[35][36][37] Unlike controlled test tube conditions, the fate of anthocyanins in vivo shows they are poorly conserved (less than 5%), with most of what is absorbed existing as chemically modified metabolites destined for rapid excretion.^[38]

When the entire scientific literature to date and putative health claims of açaí are assessed, experts concluded in 2011 that the fruit is more a phenomenon of Internet marketing than of scientific substance.^[39][40]

[edit]Juice blend studies

Various studies have been conducted that analyze the antioxidant capacity of açaí juice blends to pure fruit juices or fruit pulp. Açaí juice blends contain an undisclosed percentage of açaí.

When three commercially available juice mixes containing unspecified percentages of açaí juice were compared for in vitro antioxidant capacity against red wine, tea, six types of pure fruit juice, and pomegranate juice, the average antioxidant capacity was ranked lower than that of pomegranate juice, Concord grape juice, blueberry juice, and red wine. The average was roughly equivalent to that of black cherry or cranberry juice, and was higher than that of orange juice, apple juice, and tea.^[41]

The medical watchdog website Quackwatch noted that "açaí juice has only middling levels of antioxidants — less than that of Concord grape, blueberry, and black cherry juices, but more than cranberry, orange, and apple juices." The extent to which polyphenols as dietary antioxidants may promote health is unknown, as no credible evidence indicates any antioxidant role for polyphenols in vivo.^[42][43]

[edit]Other uses

Orally administered açaí has been tested as a contrast agent for magnetic resonance imaging of the gastrointestinal system.^[44] Its anthocyanins have also been characterized for stability as a natural food coloring agent.^[45]