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Allanblackia oil is a vegetable oil that comes from the seeds of the Allanblackia tree. This tree can be found in the wet tropical belt of Africa. Because of its unique blend of fatty acids, the oil from Allanblackia seeds has melting properties that make it excellent to use as structuring fat in food products, e.g. margarines.

Currently, Allanblackia seeds are harvested in the wild to produce the oil, but these producers cannot produce enough oil to meet market demand. Finding sustainable ways to increase production could bring many social, environmental, and economic benefits to the communities which produce Allanblackia. To ensure increased production is sustainable and benefits the communities growing the trees, a number of organizations have collaborated to develop a set of standards and methods as guidelines for increasing Allanblackia production. Other organizations are working to establish tree nurseries and other sustainable means of domesticating Allanblackia.

Allanblackia tree

Origin

Allanblackia oil is an edible vegetable oil derived from the seeds from the fruits of the Allanblackia tree. This is an evergreen tree producing big brown fruits. Inside those fruits are the seeds that contain the Allanblackia oil.[1]

The genus Allanblackia, which belongs to the Clusiaceae family, consists of nine (possibly ten) tree species, all restricted to Africa. All members of the genus are dioecious(separate male and female trees). There are nine published species of Allanblackia, mostly very similar to each other. The Allanblackia tree is commonly found in the wet tropical rain belt of West, Central and East Africa (from Sierra Leone to Tanzania). It grows primarily in tropical rainforests, but can also be found on cultivated farmland areas. Currently, the most important source of Allanblackia oil is the Allanblackia stuhlmannii tree which is found in the North east of Tanzania in the Eastern Arc mountains Other sub-species are Allanblackia parviflora (Upper Guinea, from Ghana westwards) and the Allanblackia floribunda (Nigeria, Democratic Republic of Congo, Angola). These species occur in moist low-land areas (Allanblackia parviflora, Allanblackia floribunda) or up-land rain forests (Allanblackia stuhlmannii).[2][3] The Allanblackia trees are single stemmed, up to 40 meters tall, with whorled branches. The tree will start fruiting at the age of about 8 years and in know to fruit for a long period (likely > 50 years). The fruits of the tree are amongst the biggest of all plants in the African rainforest (particularly Allanblackia stuhlmannii). A fruit can weigh up to 7 kilograms (average 4 kg) of which 20% is wet seeds (40-50 seeds per pod).[4][5][6]

Allanblackia name

The Allanblackia tree was named in honour of the botanist Allan Black (Scotland, 1832). He was the first curator of Kew Gardens and was responsible for the private collection of Charles Darwin. Very respected amongst his peers, he unfortunately died at a young age in Chennai, India and the Allanblackia tree was named in his memory. The name of the Allanblackia tree used by the indigenous people in Tanzania is actually Msambu of Mkimbo in Swahili or sometimes Mkani (Mkanyi, Mkany) in local languages.[7] In Nigeria area of River State the local name used is Obiobo Obo.

Allanblackia seed oil

Composition

The Allanblackia seeds consist of a soft fruit body mesocarp surrounded by hard wooden hull. De-hulled and dried Allanblackia floribunda seeds from Ghana contain up to 70% oil.[2][6][8] Taking the weight of the hull into account, the oil content is in the range of 40-50%. Allanblackia seed oil is unusual in that it is composed of only a few triglycerides, derived from palmitic, oleic, and stearic acids. This is similar to other tropical fats like shea and cocoa butter.[9][10] However, Allanblackia has an unusually high stearic acid content above 50%. More specifically Allanblackia seed oil contains 52-58% stearic acid, 39-45% oleic acid and 2-3% palmitic acid.[1][2][4][6][11][12][13][14]

A key characteristic is that the fatty acids are organized into a two main triglycerides. These are called 1,3-distearoyl-2-oleoyl-glycerol (abbreviated as SOS at an average level of 69%) and 1,2-dioleoyl-3-stearoyl-sn-glycerol (abbreviated as sn-SOO at an average level of 23%).[1][9][13]

This simple triglyceride composition provides the Allanblackia seed oil with very steep melting behavior.[9][10] This composition makes it useful for making food products such asmargerine, without any further modification like fractionation of fractional crystallization. The melting point is around 34 °C. Specific physical characteristics of SOS-SOO mixtures, like fat crystallization aspects, have extensively been investigated in model systems.[15]

Characteristic Unit Value
Melting range °C 42-44
(Slip) melting point °C 34-35
Solids value - 20 [°C] % 73.5
Solids value - 30 [°C] % 46.5
Solids value - 40 [°C] % 0
Refractive index [60 °C] - 1,46
Specific gravity [60 °C] kg/dm3 0.89
Saponification value mg KOH/g 200
Unsaponifiable matter % 0.54-0.65
Iodine value g/100g 35-39

Seed production

Introduction

The volumes of Allanblackia seeds, and hence seed oil, produced until now very low. The volume of allanblackia seed oil is in the range of 100 metric tonnes per annum only.[5][16][17]

These volumes are generated by wild-harvesting mainly done by collectors in Tanzania. When initial studies on the potential of wild-harvesting were done in the early 2000s, the expectations were very high predicting annual production of up to 40,000 tonnes of seeds. In reality only a few tonnes of seeds were harvested in the first year as the number of wild Allanblackia trees that could actually be harvested had severely been overestimated.[18]

Since early 2009, NGOs such as The World Agroforestry Centre (ICRAF), the International Union for the Conservation of Nature (IUCN) and commercial parties have been conducting research programs to investigate the potential to increase the annual production volumes by looking at increased wild-harvesting as well as sustainable domestication of the tree. Through the plantation of the tree with local farmers in Tanzania, Ghana and Nigeria, the production volumes are expected to increase in the coming decade, once these trees are old enough to starting producing fruits and big enough to carry more of the large fruit pods.[5][16][19][20][21]

Wild harvesting

Increasing the volumes obviously must be done sustainably and hence socio-economic and environmental aspects are being looked at. For example, the value of Allanblackia as a new cash (annual) crop for Africa means training of local communities not to cut Allanblackia trees for use as timber and firewood. But doing so is also a means of helping to conserve local biodiversity. The Union for Ethical Biotrade (UEBT) has developed a standard and a verification framework against which the sustainability of the Allanblackia supply chain can be audited and approved.[22] UEBT is a member of the International Social and Environmental Accreditation and Labelling (ISEAL) Alliance, which promotes sustainability standards.[23]

Domestication

Wild harvesting as a production method is limited because there are not enough trees to satisfy demand and Allanblackia’s flowering and fruiting behavior is erratic. Since 2006, Novel Development Tanzania has been involved in a domestication program together with the World Agroforestry Centre (ICRAF) to domesticate the species using participatory tree domestication approach. The program includes community sensitization, exploration, participatory selections of superior mother trees, conservation in field gene banks, development of agroforestry systems with Allanblackia and market development. Secondly, the program consists of developing asexual and sexual propagation protocols, which are necessary to overcome challenges in multiplication such as seed dormancy, long juvenile phase and high variability of desired traits. The domestication program of Allanblackia through public-private partnership and participatory tree domestication could serve as a model for domestication of other underutilized African tree species of high economic potential.[24]

Oil production

Seed harvesting and drying

  • An individual tree can produce up to 300 fruits a year, with the average bearing 100 to 150 in a good season. In Ghana Allanblackia parviflora fruits have been reported to have a weight of 1.5–2 kg.[25] The fruit pods from the Tanzanian Allanblackia stuhlmannii weigh on average 4 kilogram with a maximum up to 7 kilograms. The may containing up to 40-50 separate seeds embedded in a pulp.[4][5][19]
  • When the fruit are ripe they will fall down to the ground. Harvesters will collect these fallen fruits and manually extract and clean the seeds. These are than laid out in the sun to dry which will generally take 1–2 weeks.[16]

Seed quality

  • After drying the seeds are bagged and brought to collection centers by the farmers / collectors for sale.
  • Upon drying the color of the inside (mesocarp) of the seeds will change from off-white (wet) to ocreous-brown (dry).
  • In the collection centers this change of color is used to determine the overall quality of drying of each bag of seeds (20–40 kg) by testing a random sample of seeds.
  • Next to that seeds are checked for the amount of dirt, while broken seeds are removed. Also seeds infected by insects are removed. Such seeds can be recognized by small holes present in the outer shell of the seeds.
  • The seeds collected are put into bags again and brought to a local warehouse waiting to be transported to the oil mill.

Seed and oil processing

  • From local warehouses the seeds are brought to a central warehouse at the oil mill to press-out the oil. In Tanzania the Allanblackia Oil Mill is located in the coastal city of Tanga, in the north-east of the country.
  • In the mill the seeds are taken out of the bags and stored locally until crushing. For the crushing a seed-oil press is used, separating the oil from the residual fibrous cake.
  • The crude oil is decanted and filtered to remove remaining solids.
  • The oil is than stored at 40-45 °C to keep it liquid and pumped to an Iso-container for further transport.
  • The remaining cake from the pressing still contains fibers and residual oil] and therefore it is used as a renewable source of energy in the oil mill, generating steam in a high pressure steam boiler.
  • After transport to the country where the final product manufacturing will take place, the oil is purified according to standard practices to remove unwanted free fatty acids and off-taste, making the oil ready for use in manufacturing of products, e.g. margarines.

Application in product

Historical use

In Tanzania the use of allanblackia seed oil goes back almost a century. It has been reported that during the First World War allanblackia oil was already tested as a cocoa butter alternative. Also in the seventies the such application was again explored in Europe. However the application never hit the market because larger volumes of the oil were simply not available due to the lack of an organized supply chain.[5][26]

Nowadays there is still in hardly any local use of Allanblackia seed oil as people prefer use of easily available liquid oils and cheap industrial soaps.[16] The allanblackia tree has predominantly been used for timber in the last decades and hence the number of trees has significantly reduced . Most of the allanblackia trees nowadays remaining in the wild are growing in the East Usambara Mountains which provides the right climate for this tree. As a result, even today the volumes of oil available from wild-harvesting are still very small.[5][16]

Current use

The major application potential identified today is in the use as a structuring fat to produce low-trans margarines and dairy cream alternatives, and as cocoa butter equivalent in confectionery applications.[1][9][20] In the European Union as of December 2014, all different types of vegetable oils will be listed on the ingredient label of food products using those ingredients.[27] Recently Allanblackia seed oil was introduced in margarine and can be found as such on the product ingredient list.

See also

References

  1. ^ a b c d EU Food Safety Authority (2007), Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies on a request from the Commission related to the safety of Allanblackia seed oil for use in yellow fat and cream based spreads' (PDF)
  2. ^ a b c Adubofuor; et al. (2013). "Nutrient composition of A. Parviflora seed kernels and oil compared with some plant fats and oils and application of the oil in soap preparation". J Cereals Oil Seeds. 4 (1): 1–9. doi:10.5897/jco12.020.
  3. ^ "IUCN Red list".
  4. ^ a b c Atangana A.R.; et al. (2011). "Tree to tree variation in stearic and oleic acid content in seed fat from Allanblackia floribunda from wild stands: Potential for tree breeding". Food chem. 126 (4): 1579–1585. doi:10.1016/j.foodchem.2010.12.023.
  5. ^ a b c d e f Pye-Smith (2009) 'Seeds of hope', World Agroforestry Centre, Nairobi, Kenya "Seeds of hope" (PDF).
  6. ^ a b c Foma, M.; et al. (1985), "Kernels of seven plants species of Zaire", LACOS, 62 (5): 910
  7. ^ Ruffo C.; et al. (2002), "'Edible Wild Plants of Tanzania'", Publication Regional Land Management Unit (RELMA) Swedish International Development Cooperation Agency (Sida), ISBN 9966-896-62-7
  8. ^ Wilfred S.; et al. (2010), "'Optimum conditions for expression of oil from Allanblackia floribunda seeds and assessing the quality and stability of pressed and solvent extracted oil'", African J. Food Science, 4 (9): 563–570
  9. ^ a b c d Lovett P. (2014), "Natural butters:fractionation alternatives", Personal care, March
  10. ^ a b Timms R.E. (2003), "Confectionery fats handbook", The Oily Press Lipid Library, 14 (5): 173–176
  11. ^ Eckey E.W. (1954), "'Vegetable Fats and Oils'", Reinhold Publishing Crop: 687
  12. ^ Hilditch (1958), "'Chemical Contribution of Natural Fats'", TANG Tr. Bull, part1: 13
  13. ^ a b Mattson F. H. and Luttan E.X. (1958), "'The Specific Distribution of Fatty Acids in the Glycerides of Animal and Vegetable Fats'", J. Biol. Chem., 233 (4): 868–871
  14. ^ "Minor oil crops — Individual monographs (Allanblackia-Almond-Chaulmoogra-Cuphea spp.-Jatropa curgas)". Fao.org. Retrieved 2013-11-21.
  15. ^ Zhang; et al. (2009). "Thermal and structural properties of binary mixtures of 1,3-distearoyl-2-oleoyl-glycerol (SOS) and 1,2-dioleoyl-3-stearoyl-sn-glycerol (sn-OOS)". J Therm Anal Calorim. 98: 105–111. doi:10.1007/s10973-009-0451-3.
  16. ^ a b c d e Andersson M.S. (2010), Allanblackia nuts in tropical Africa: a new source for food, oil and ecosystem services (PDF)
  17. ^ Philemon L. (2010), Wild plant that can turn into gold
  18. ^ Achten W. (2014). "Opportunities and Constraints of Promoting New Tree Crops — Lessons Learned from Jatropha". Sustainability. 6: 3213–3231. doi:10.3390/su6063213.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  19. ^ a b Attipoe L, van Andel A, Nyame SK. (2006). The Novella project: developing a sustainable supply chain for Allanblackia oil. In: Ruben R, Slingerland M, Nijhoff H (eds) Agro-food chains and networks for development. Springer, Amsterdam,. pp. 179–189.{{cite book}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
  20. ^ a b Ochieng C.M.O. (2007). "Revitalising African agriculture through innovative business models and organizational arrangements : promising developments in the traditional crops sector". J. Modern African Studies. 45: 143–169. doi:10.1017/s0022278x0600231x.
  21. ^ Buss C. (2010). "Allanblackia an ingredient for poverty reduction ?". Rural. 21 (3): 37–39.
  22. ^ UEBT "Ethical Biotrade Standard".
  23. ^ "ISEAL".
  24. ^ Ofori D.A. Ofori, Kehlenbeck K., Munjuga M., Asaah A., Kattah C., Rutatina F., Jamnadass R. (2013), Allanblackia species: a model for the domestication of high potential tree crops in Africa, ISHS Acta Horticulturae 979: II International Symposium on Underutilized Plant Species: Crops for the Future — Beyond Food Security{{citation}}: CS1 maint: multiple names: authors list (link)
  25. ^ Peprah T.; et al. (2009). "Reproductive biology and characterization of Allanblackia parviflora A. Chev. in Ghana". Genet. Resour. Crop Evol. 56: 1037–1044. doi:10.1007/s10722-009-9475-6.
  26. ^ Meshack C. (2005), Indigenous knowledge of Allanblackia stuhlmannii in the East Usambara Mountains (PDF)
  27. ^ "New EU law on Food Information to Consumers".
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