Ginkgo Nut

The ginkgo is a tall deciduous tree with fan-shaped leaves, and female trees bear plum-like fleshy seeds that turn yellow-orange in autumn. The outer layer smells strongly of rancid butter when it breaks open because of butyric acid. Inside is a smooth, pale, hard shell about the size of a large almond, and within that a soft, ivory-to-jade-green kernel with a thin brown skin. Cooked, the kernel becomes glossy, sticky and slightly chewy, with a mild, faintly bitter, chestnut-like flavour. Ginkgo nuts are sold shelled or in-shell, fresh, canned, vacuum-packed or roasted, mostly in Asian groceries.

Ginkgo biloba is the sole survivor of an ancient lineage of trees whose relatives appear in the fossil record for around 200 million years. Wild populations are believed to have survived in China, and the species has been cultivated there for many centuries. The common name ginkgo is often explained as a European misspelling of the Japanese ginkyo, derived from the Chinese for silver apricot, yinxing. The species name biloba refers to the two lobes of the leaf. The Chinese name for the seed, bai guo, means white fruit.

Ginkgo has been planted around Buddhist temples and in imperial gardens in China, Korea and Japan for centuries, and the seeds were carried by monks and travellers across those regions. Records of ginkgo seed use in Chinese medicine and cooking go back many centuries, and the kernels were prized as a food for celebrations and winter feasts.

The tree reached Europe in the early eighteenth century, when the German physician Engelbert Kaempfer described it from Japan, and it then spread through botanical gardens. It became popular in cities because it tolerates pollution and is resistant to many pests, which is why male trees are widely planted along streets; female trees are avoided in urban settings because of the odour of the fallen fruit. The survival of ginkgos in Hiroshima after the 1945 bombing made the tree a symbol of resilience in Japan.

Today, China, Japan and Korea remain the main producers and consumers of ginkgo nuts. They appear in dishes such as chawanmushi, congee and dessert soups, and are a traditional New Year food in some regions, while leaf extracts have developed into a separate global supplement industry.

Shelled kernels are boiled, roasted or stir-fried and added to savoury custards such as chawanmushi, congee, braised vegetable dishes, hot pots and sweet dessert soups. In Japan they are skewered and grilled as an izakaya snack and served with salt. In Chinese cuisine they are a traditional ingredient in vegetarian banquet dishes. Traditionally the seeds have also been used in folk medicine for coughs and bladder complaints. The shell can be cracked with a nutcracker, and the kernels are often blanched to remove the skin. Fresh nuts store best refrigerated.

Cooked ginkgo kernels provide starch, some protein and small amounts of minerals and vitamins, but they are eaten in small portions as a delicacy rather than a staple. Most research on ginkgo relates to leaf extracts, not to the seeds, so findings on memory or circulation do not transfer to the nuts. The seeds contain compounds studied for antioxidant activity in the laboratory, but there is no reliable evidence of therapeutic benefit from eating them.