| Butyrospermum parkii | |
|---|---|
| Shea nuts | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Ericales |
| Family: | Sapotaceae |
| Genus: | Vitellaria |
| Species: | V. paradoxa |
| Binomial name | |
| Vitellaria paradoxaButyrospermum parkii Kotschy |
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| Synonyms | |
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Butyrospermum paradoxa |
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Vitellaria paradoxa, also classified as Butyrospermum parkii and B. paradoxa, commonly known as shea tree, shi tree, pronounced /ˈʃiː/ or /ˈʃiː.ə/, vitellaria or karité, is a tree of the Sapotaceae family indigenous to Africa, occurring in Mali, Cameroon, Congo, Côte d'Ivoire, Ghana, Guinea, Togo, Nigeria, Senegal, Sudan, Burkina Faso and Uganda. The shea fruit consists of a thin, tart, nutritious pulp that surrounds a relatively large, oil-rich seed from which shea butter is extracted.
The Shea tree is a traditional African food plant. It has been claimed to have potential to improve nutrition, boost food supply in the "annual hungry season[1]", foster rural development and support sustainable landcare.[2]
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The tree is perennial and starts bearing its first fruits when 10–15 years old; full production is attained when the tree is about 20–30 years. It then produces nuts for up to 200 years.
The fruits resemble large plums and take 4–6 months to ripen. The average yield is 15–20 kilograms of fresh fruit per tree, with optimum yields up to 45 kg. Each kilogram of fruit gives approximately 400 grams of dry seeds.
Shea butter is composed of five principal fatty acids: palmitic, stearic, oleic, linoleic, and arachidic (Table 1). The fatty acid composition is dominated by stearic and oleic acids, which together account for 85–90% of the fatty acids. The relative proportion of these two fatty acids affects shea butter consistency. The high stearic acid content gives the shea butter its solid consistency, while the percentage of oleic acid influences how soft or hard the shea butter is, depending on ambient temperature.
The proportions of stearic and oleic acids in the shea kernels and butter differ across the distribution range of the species. Ugandan shea butter has consistently high oleic acid content, and is liquid at warm ambient temperatures. Ugandan shea butter fractionizes into liquid and solid phases, and is the source of liquid shea oil. The fatty acid proportion of West African shea butter is much more variable than Ugandan shea butter; the oleic content ranges from 37 to 55%. Variability can be high even locally, and a tree that produces hard butter can be located right next to one that produces soft butter. Nuts are gathered from a wide area for local production, so shea butter consistency is determined by the average fatty acid profile of the population. Within West Africa, shea butter from the Mossi plateau region of Burkina Faso has higher average stearic acid content, and is therefore harder than shea butter from other West African regions.
| Fatty Acid | Mean | Min | Max |
|---|---|---|---|
| 16:0 Palmitic | 4.0 | 2.6 | 8.4 |
| 18:0 Stearic | 41.5 | 25.6 | 50.2 |
| 18:1 Oleic | 46.4 | 37.1 | 62.1 |
| 18:2 Linoleic | 6.6 | 0.6 | 10.8 |
| 20:0 Arachidic | 1.3 | 0.0 | 3.5 |
Phenolic compounds are known to have antioxidant properties. A recent study characterized and quantified the most important phenolic compounds in shea butter (4). This study identified 10 phenolic compounds in shea butter, eight of which are catechins, a family of compounds being studied for their antioxidant properties. The phenolic profile is similar to that of green tea, and the total phenolic content of shea butter is comparable to virgin olive oil. Also, this study was performed on shea butter that had been extracted with hexane, and the authors note that alternative extraction methods — such as traditional extraction — may result in higher phenolic levels. Furthermore, they note that the catechin content alone of shea kernels is higher than the total phenolic content of ripe olives.
This study also found that the overall concentration and relative percentages of different phenolic content in shea kernels varied from region to region. The authors hypothesized that the overall concentration of phenols in shea kernels is linked to the level of environmental stress that the trees endure.[3][4]
The shea tree grows naturally in the wild in the dry savannah belt of West Africa from Senegal in the west to Sudan in the east, and onto the foothills of the Ethiopian highlands. It occurs in 19 countries across the African continent, namely Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Ethiopia, Ghana, Guinea Bissau, Côte d'Ivoire, Mali, Niger, Nigeria, Senegal, Sierra Leone, Sudan, Togo, Uganda, Democratic Republic of the Congo and Guinea.
A reflection of its extensive range of occurrence nearly 5,000 km from Senegal (west) to Uganda (east) across the African continent.
Shea nut "butter" has many uses and may or may not be refined. In the West, shea butter is mostly used for cosmetics. Throughout Africa it is used extensively for food and medicinal purposes, and is a major source of dietary fat. The fruit is edible and delicious. It tastes roughly like a fig.
The common name is shíyiri or shísu (lit. 'shea tree') in the Bamana language of Mali. This is the origin of the English word, and is correctly pronounced "shee" to rhyme with "tea." The tree is called ghariti in the Wolof language of Senegal, which is the origin of the French name of the tree (and of its butter), "karité".
The tree was formerly classified in the genus Butyrospermum, meaning 'butter seed.' The species name parkii honors Scottish explorer Mungo Park, who learned of the tree while exploring Senegal. The tree is now classified using the binomial name Vitellaria paradoxa. That Mungo Park was Scottish is reflected in the English spelling of the tree, nut, and butter as shea with a final -ea.