Marula Oil
Botanical: Sclerocarya birrea
Family: Anacardiaceae
Common: Marula, cider tree, maroela
Description
(Palmer and Pitman, 1972). The small dark red flowers are unisexual and found in fragrant clusters at the end of the branches, attracting insects in abundance. The insect humming from a flowering tree can often be heard some distance away. The compound leaves are grey-green in colour, but turn pale yellow prior to being shed. Denuded of leaves, the top branches appear abnormally thick and erect, like upturned fingers (digitaliform). The leaves attract many butterflies, including the magnificent green lunar moth, whose large silkworm-like cocoons, are used by Southern Africans, as ankle rattles for dancing. The tree remains bare for several months of the year (Watt and Breyer-Brandwijk, 1962).
Fruit
The Marula tree is in the same family as the mango. The plum sized drupes are covered in a soft, leathery, pale green-yellow exocarp which encloses the juicy white flesh (Hall, 2002). The exotic flavour of the fruit is often compared to a cocktail of guava, lychee, apple and pineapple, and has a distinctive scent. The fruit contains a large hard stone, surrounding 2 or more edible seeds, rich in oil. Marula trees are distinctive for their exceptional fruit and oil yields, making them very easy to harvest. In fact this characteristic has not only been noted by humans, but also by elephants who will travel miles to gorge on the fruits (Hutchings et al, 1996). Importantly, the Marula fruit harvest occurs at the beginning of the school year making the cash income from their sale very important for the payment of school fees and clothing (Wynberg et al, 2003).
Distribution
The Marula tree is one of the great trees indigenous to Southern Africa. It’s drought resistance make it ideally suited to Namibia, Botswana, Zambia and Zimbabwe where it is found in abundance from bushveld to woodlands. Wherever it grows it is venerated and preserved by Africans for the abundance and reliable harvest of edible fruits.
Traditional Uses
Archaeological evidence has confirmed that the Marula tree has been a central part of the Southern African way of life for thousands of years; hoards of Stone Age Marula stones have been found in Zimbabwean caves, with carved tools and piles of shells in close proximity (Hutchings et al, 1996). The same tools are used to this day to crack the stones and extract the seeds. It is likely that the modern day uses for the tree have also been passed down the generations from Stone Age homo sapiens. Every part of the tree is utilised for an incredible variety of domestic needs. The fruits are brewed into a popular beer; the bark is used medicinally to treat diarrhoea, diabetes, fever and malaria; the leaves are used to make a relish; and the hard wood makes excellent kitchen utensils. However, it is the oil from the Marula seeds that has come to give the Marula tree its spiritual status. The seeds are so full of oil that a squeeze with the hand can release a rich yield. This healing oil is used as a cosmetic, by Southern African women, and is massaged onto the skin of their face, feet and hands. Across the generations it has proven to protect against dry, cracking skin and its moisturising properties are so effective that it is also used to treat leather and in preserving meat. Hence within the Zulu tribe, the Marula tree symbolizes women’s fertility, softness and tenderness, and new-born baby girls are welcomed into the world with traditional Marula ceremonies (Palmer + Pitman, 1972).
Known Properties
Marula oil is a clear, pale, yellowish-brown colour and has a pleasant aroma. Studies have shown that the oil is highly nutritional and extraordinarily stable, containing a large proportion of mono-unsaturated fatty acids and natural antioxidants (Burger et al, 1987; Eromosele & Paschal, 2003; Glew et al, 2004; Houghton, 1999). Marula oil contains a similar fatty acid composition to olive oil however it is 10 times more stable to oxidation. Easily absorbed, containing high proportions of oleic acid (70-78%), as well as the essential linoleic fatty acid (4-7%) combine to make the oil ideal for topical application. Marula oil has also shown to improve skin hydration, skin smoothness and reduce redness. Marula oil scored higher than sweet almond oil for each of these properties.
Marula oil has been shown to have free radical scavenging properties higher than most oils oil the market.
Technical specifications
INCI name: |
Sclerocarya birrea oil |
CAS No: |
68956-68-3 |
EINECS No: |
273-313-5 |
Description: |
Tawny coloured oil, which is liquid at room temperature |
Specific gravity: |
0.91-0.92 |
Iodine Value gI2/100g: |
70-80 |
Saponification Value mgKOH/g: |
188-196 |
Acid value mg KOH/g: |
5max |
Peroxide value mEq O2/Kg: |
15max |
Fatty Acid Composition
Parameter |
Ranges |
|---|---|
16:0 palmitic % |
9.0-12 |
18:0 stearic % |
5.0-8.0 |
18:1 oleic % |
70-78 |
18:2 linoleic % |
4.0-7.0 |
18:3 -linolenic % |
0.1-0.6 |
20:0 arachidic % |
0.3-0.7 |
MANUFACTURING PROCESS: |
Cold pressed (T<60°C) - no solvents or chemicals used. |
|
Decanted to separate fines. |
STORAGE: |
keep away from light, heat (T<20°C) and in a dry place. Sparge with Nitrogen |
PACKAGING: |
5, 25 litre and 200kg drums. |
Applications
Skin: to treat dry, chapping skin. To maintain hydrated, smooth skin as well as reducing redness. Can be used around the eyes. A good massage oil. Antiaging face cream.
Baby care: massage oil
Shampoo: Dry, damaged and fragile hair
Lipstick: ingredient
Food: antioxidant properties for the nutraceutical industry
Selected references
Burger, A. E. C. et al (1987) Composition of the kernel oil and protein of the marula seed. South African Journal of Science, 83 (November/ December): 733-735.
Eromosele, C. O. and Paschal, N. H. (2003) Short Communication: Characterization and viscosity parameters of seed oils from wild plants. Bioresource Technology, 86: 203-205.
Glew, R. S. et al (2004) Nutritional analysis of the edible pit of Sclerocarya birrea in the Republic of Niger (daniya, Hausa). Journal of Food Composition and Analysis, 17: 99-111.
Hall, J. (2002) Sclerocarya birrea (A.Rich.) Hoscht. In Plant Resources of Tropical Africa. Precursor. (Eds, Oyen, L. and Lemmens, R.), PROTA Programme, Wageningen, the Netherlands, pp. 127-131.
Houghton, C. (1999) New Natural Oils and their Properties. Anglia Oils Ltd., Bulk Speciality Division.
Hutchings, A. et al (1996) Zulu Medicinal Plants: An Inventory, University of Natal Press, Pietermaritzburg in association with University of Zululand, Kwblangezwa and National Botanical Institute, Cape Town.
Leakey, R. R. B. (1999) Potential for novel food products from agroforestry trees: a review. Food Chemistry, 66: 1-14.
Palmer, E. and Pitman, N. (1972-1974) Trees of southern Africa Balkema, Cape Town, pp. 226-246.
Watt, J. M. and Breyer- Brandwijk, M. G. (1962) Anacardiaceae In Medicinal and poisonous plants of southern and eastern Africa. Livingstone, Edinburgh & London, pp. 151-154.
Wynberg, R. et al (2003) Marula policy brief: Marula commercialisation for sustainable and equitable livelihoods. Forests, Trees and Livelihoods, 13: 203- 215.