The oysternut, or kweme as it is known in northern and central Tanzania, is the seed of the liana Telfairia pedata. This species is native to Tanzania (where it is known as kweme) and northern Mozambique, and can reach a height of 20 – 30 meters. It also occurs in the hot and humid areas of central and eastern Uganda (where it is known as kulekula), and plays a major part in many cultural events.
It begins producing fruits after two years and remains productive for up to 20 years. Seeds obtained from vines in cold, rainy areas are considered of better quality than those from mountain plants. The long fruits are about the size of an average watermelon and contain multiple seeds. The flat, round seeds are 3 – 4 centimeters in diameter. They are harvested when the fruits fall from the vine and break open at the end of the rainy season. They are then consumed fresh or dried for later consumption. The sand-colored shell has a fibrous texture, while the inside is green and oily, with a taste that is reminiscent of broad beans and green almonds. Seeds can be eaten raw or roasted and crushed in a mortar to create a paste to add to other vegetable or meat dishes. Oysternuts have a high protein content (about 25%) and high oil content (55 – 60%). The oil has a delicious, sweet flavor. Oysternuts are often consumed by pregnant women. In Uganda, the nuts are often made into soups and mixed with mushrooms to be served to the husband during wedding ceremonies, as a sign of love, as well as to the special guests.
Oysternuts are still collected for personal consumption, but are no longer found on the local market, though local farmers have expressed interest in cultivating the vines if there were demand among consumers. Another reason this product is at risk of extinction is the low germination rate of the seeds (about 30%) in conditions where seed humidity is lower than 40%, and so more information is needed on proper seed storage to cultivate this species.
Image: @ Valentina Meraviglia