途上国森林ビジネスデータベース

The tree starts bearing fruits after 18–25 years. A bumper year comes every five years or so. Fallen fruits are collected. Along rivers, fences made from bamboos or other materials are built to collect fruits that float down the rivers. The egg-shaped fruits have “wings” and the size, which varies depending on the species, is approximately 5 cm long and 3 cm wide and is covered with a husk (epicarp). The color is brown-black. The fruit’s fat content is 45–70%. Due to their high germination capacity, the fruits quickly decompose after absorbing moisture. A dry fruit yield of 1,138 kg/ha has been reported.

Damages to the fruits caused by insects (Lepidoptera and Coleoptera) during storage increases the content of free fatty acids, resulting in quality loss of the oil. Other reported pests include Poecilips gedeanus (Beaver) and Tirathaba spp. (Brady)

Storage of fruits, husk removals, oil extraction method

There are several husk removal methods for extracting oil: 1) make the fruits germinate in flowing water, 2) make the fruits germinate in soil, 3) steam the fruits in a kiln at 55 ˚C, and 4) mechanically break the fruits. The broken husks can be removed by hand. Removed nuts are dried in the sun for five to seven days and stored. The nuts can be dried to a water content of 7% to prevent decomposition during storage.

To extract oil, local villagers boil the fruits in a pan, put them in a rattan bag, hold the bag between logs of wood, and squeeze the logs together. The extracted oil is stored in bamboo cylinders. For industrial purposes, solvent extraction with hexane is used. Extracted oil is then purified and bleached. Post-extraction residues contain tannic acid and can be used as animal feed.

Main fatty acids contained in Borneo tallow nut oil

An oil extraction and purification plant is located in Pontianak, western Kalimantan in Indonesia, which produces cacao butter made from cacao and illipe nut butter made from Borneo tallow nuts.

Export and import trends, demands in Japan

According to one report, in the peak years, Indonesia exported 41,000–50,000 t of the dry fruits annually. Till around 1990, Japan imported Borneo tallow nuts to extract oil, but has since then directly imported the vegetable oil instead of the fruits from which the oil is extracted.

In Indonesia, however, Commerce Minister’s Order No. 44/2012 added Borneo tallow nuts to the export prohibition list for raw materials. In response, the momentum toward processing the nuts domestically and exporting the finished products is strengthening.

Potential for forest-based business

Vegetable oil extracted from Borneo tallow nuts is economically important as a non-wood forestry product and has potential for striking the balance between forest preservation and the livelihood of local residents. Therefore, the tree is currently used as a plantation species for forest regeneration or community forest development projects. Western Kalimantan and western Java are home to Shorea stenoptera plantations, where the trees start bearing fruits after four years. While its ultimate purpose is wood use, if the nuts can be collected before the trees are felled, they will become a source of income for the local people, contributing to community development and the maintenance and regeneration of local rainforests.

Yearly fluctuation of “tengkawang” fruit production has been significant with the fruiting interval being irregular (from every a few years to 10 years). In fruit-bearing years, the nuts become the most important export for Sarawak. Recently, research done by CIFOR and other organizations found that Shorea species that bear fruits every year raise expectations for an annual, stable supply of the nuts, increasing its demand as an industrial raw material.