Marula oil

Marula oil is extracted from the kernels (nuts) of the Marula tree (Sclerocarya birrea), from the Anacardiaceae family. Marula oil is traditionally used in cosmetics, in food as a cooking oil and as a meat preservative and to treat leather.

Chemical structure

Marula oil contains a large proportion of monounsaturated fatty acids and natural antioxidants which make the oil very stable. The fatty acid composition of marula oil includes:^[1]

Mono-unsaturated fatty acids:

• Oleic acid (70-78 %)

Polyunsaturated fatty acids:

• Linoleic acid (4.0-7.0 %)
• Alpha-linolenic acid (0.1-0.7 %)

Saturated fatty acids:

• Palmitic acid (9-12 %)
• Stearic acid (5.0-8.0 %)
• Arachidonic acid (0.3-0.7 %)

Tocopherols, sterols and flavonoids, with antioxidant action, procyanidin, galattotannin and catechins are also found in marula oil.^[2]

Physical properties

Marula oil has a clear, light yellow colour and a nutty aroma. It has a saponification value of approximately 188-199 and a specific gravity of 0.91-0.92 (at 15°C).^[3]

Traditional uses

The Tsonga people of South Africa and Mozambique have used the oil as a moisturising body lotion for women and also as a massage oil for babies. In the past, women used Marula oil rather than water to clean themselves.^[4]

Marula oil forms also an important part of people's diets, especially for people of the Inhambane Province in Mozambique, Owambo in north central Namibia, Northern KwaZulu-Natal in South Africa and the Zvishavane district of Zimbabwe. Furthermore, marula plays an important role in the diet of Bushmen and Bantu tribes.^[5][6] The Venda utilise the oil from the kernels to preserve meat, which enables it to last up to a year. Today, Marula oil is still considered a delicacy by local people, and is added to a wide variety of traditional and modern recipes.^[4]

Applications

Studies have looked at the oxidation stability, induction period (34 hours), polar compounds, free fatty acids of Marula oil as a frying oil.^[7]

References

1. ^ Hore, D. (2004). Formulation of cosmetic skin lotions using Adansonia digitata and Sclerocarya birrea oil from Zimbabwe. University of Zimbabwe, Harare. 
2. ^ Mariod et al; Matthaus, Bertrand; Eichner, K. (2004). "Fatty acid, tocopherol and sterol composition as well as oxidative stability of three unusual Sudanese oils". Journal of Food Lipids 11 (3): 179–189. doi:10.1111/j.1745-4522.2004.01131.x. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1745-4522.2004.01131.x. 
3. ^ Hall, J., et al (2002). Sclerocarya birrea: a monograph. School of Agricultural and Forest Sciences, University of Wales, Bangor. 
4. ^ ^{a b} A History of Marula Use in North-central Namibia. Windhoek, Namibia, Eudofano Women’s Co-operative Ltd and CRIAA SA-DC.. 2001. 
5. ^ Engelter & Wehmeyer; Wehmeyer, A.S. (1970). "Fatty acid composition of oils of some edible seeds of wild plants". Journal of Agriculture and Food Chemistry 18: 25–26. doi:10.1021/jf60167a025. 
6. ^ Shackleton, S.E., et al (2002). A summary of knowledge on Sclerocarya birrea with emphasis on its importance as a NTFP in South and Southern Africa. 
7. ^ Mariod et al; Matthäus, Bertrand; Eichner, Karl; Hussein, Ismail H. (2006). "Effects of processing on the quality and stability of three unconventional Sudanese oils". European Journal of Lipid Sciences and Technology 108 (4): 298–308. doi:10.1002/ejlt.200500323.