Shea butter

Seeds of a shea tree — raw materials for oil production

Shea butter (/ˈʃiː/, /ˈʃiː.ə/, or /ˈʃeɪ/) is an off-white or ivory-colored fat extracted from the nut of the African shea tree (Vitellaria paradoxa).^[1] Shea butter is a triglyceride (fat) derived mainly from stearic acid and oleic acid. It is widely used in cosmetics as a moisturizer, salve or lotion. Shea butter is edible and is used in food preparation in Africa.^[2] Occasionally, the chocolate industry uses shea butter mixed with other oils as a substitute for cocoa butter, although the taste is noticeably different.^[3][4]

The English word "shea" comes from s’í, the tree's name in the Bambara language of Mali.^[5] It is known by many local names, e.g., karité in the Wolof language of Senegal,^[6] ori in some parts of West Africa, and many others.^[7][8]

Shea butter is a triglyceride (fat) derived mainly from stearic acid and oleic acid.

History

Accounts from as early as Cleopatra's Egypt speak of caravans bearing clay jars of valuable shea butter for cosmetic use. The funeral beds of early kings were carved in the wood of shea trees. Shea butter's skin care and healing properties were first harnessed thousands of years ago. The history of shea as a precious commodity can be traced back to Ancient Egypt, where shea butter was and continues to be used to protect the hair and skin in the fierce sun and the hot dry winds of African deserts and savannah.^[9]

Butter extraction and refining

The traditional method of preparing unrefined shea butter consists of the following steps:^[10]

Child labourers transporting crushed Shea nuts, Jisonaayili.

Traditional preparation of shea butter, Mali

• Separating/cracking: The outer pulp of the fruit is removed. When dry, the nut, which is the source of shea butter, must be separated from the outer shell. This is a social activity, traditionally done by women elders and girls who sit on the ground and break the shells with small rocks.
• Crushing: To make the shea nuts into butter, they must be crushed. Traditionally, this is done with mortars and pestles. It requires lifting the pestles and grinding the nuts into the mortars to crush the nuts so they can be roasted.
• Roasting: The crushed nuts are roasted in huge pots over open wood fires. The pots must be stirred constantly with wooden paddles so the butter does not burn. The butter is heavy and stirring it is hot, smoky work, done under the sun. This is where the slight smoky smell of traditional shea butter originates.
• Grinding: The roasted shea nuts are ground into a smoother paste; water is gradually added and the paste is mixed well by hand.
• Separating the oils: The paste is kneaded by hand in large basins and water is gradually added to help separate out the butter oils. As they float to the top, the butter oils, which are in a curd state, are removed and excess water squeezed out. The butter oil curds are then melted in large open pots over slow fires. A period of slow boiling will evaporate any remaining water.
• Collecting and shape: The shea butter, which is creamy or golden yellow at this point, is ladled from the top of the pots and put in cool places to harden. Then it is formed into balls.

Industrially, a mechanical sheller such as the universal nut sheller may be used. The refined butter may be extracted with chemicals such as hexane or by clay filtering.

Composition and properties

Shea butter extract is a complex fat that in addition to many nonsaponifiable components (substances that cannot be fully converted into soap by treatment with alkali) contains the following fatty acids: oleic acid (40-60%), stearic acid (20-50%), linoleic acid (3-11%), palmitic acid (2-9%), linolenic acid (<1%) and arachidic acid (<1%).^[11]

Shea butter melts at body temperature. Proponents of its use for skin care maintain that it absorbs rapidly into the skin, acts as a "refatting" agent, and has good water-binding properties.^[12]

Uses

Shea butter soap.

Shea butter is mainly used in the cosmetics industry for skin- and hair-related products (lip gloss, skin moisturizer creams and emulsions, and hair conditioners for dry and brittle hair). It is also used by soap makers, typically in small amounts (5-7% of the oils in the recipe), because it has plenty of unsaponifiables, and higher amounts result in softer soaps that have less cleaning abilities. Some artisan soap makers use shea butter in amounts to 25% - with the EU regulating the maximum use around 28%, but it is rarely the case in commercially produced soap due to its high cost against oils like palm or pomace (olive). It is an excellent emollient for people who suffer dry skin conditions. No evidence shows it is a cure, but it alleviates the pain associated with tightness and itching.

In some African countries such as Benin, shea butter is used for cooking oil, as a waterproofing wax, for hairdressing, for candle-making, and as an ingredient in medicinal ointments. It is used by makers of traditional African percussion instruments to increase the durability of wood (such as carved djembe shells), dried calabash gourds, and leather tuning straps.

Shea butter can be an ingredient of organic broth.^[13]

In the UK and other countries, it is incorporated into assorted tissue products, such as toilet paper.^[14]

Medicinal

Shea butter is sometimes used as a base for medicinal ointments. Some of the isolated chemical constituents are reported to have anti-inflammatory,^[15] emollient, and humectant properties. Shea butter has been used as a sunblocking lotion and has a limited capacity to absorb ultraviolet radiation.^[3]

In Ghana, shea butter, locally known as nkuto (Akan) or nku (Ga), is applied as a lotion to protect the skin during the dry Harmattan season.^[6]:p.8

In Nigeria, shea butter is used for the management of sinusitis and relief of nasal congestion.^[16] It is massaged into joints and other parts of the body where pain occurs.

Classification

The United States Agency for International Development and other companies^[17] have suggested a classification system for shea butter separating it into five grades:

• A (raw or unrefined, extracted using water)
• B (refined)
• C (highly refined and extracted with solvents such as hexane)
• D (lowest uncontaminated grade)
• E (with contaminants).

Commercial grades are A, B, and C. The color of raw (grade A) butter ranges from cream (like whipped butter) to grayish yellow. It has a nutty aroma which is removed in the other grades. Grade C is pure white.^[18] While the level of vitamin content can be affected by refining, up to 95% of vitamin content can be removed from refined grades (i.e., grade C) of shea butter while reducing contamination levels to undetectable levels.^[19]

See also

• Shea nut and butter production in Burkina Faso
• Shea Yeleen, a social enterprise that trains women-owned shea butter cooperatives
• List of butters

References

Wikimedia Commons has media related to Shea butter.

Look up shea butter in Wiktionary, the free dictionary.

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