Watermelon Seed

Watermelon seeds are teardrop-shaped, 8 to 15 millimetres long and flat, with a hard outer shell that may be black, brown, red, tan or white depending on the variety. Inside is a pale, tender kernel with a mild, nutty, slightly sweet taste. Some varieties are bred especially for their seeds, with large, easy-to-crack seeds and little sweet pulp. The seeds of the common sweet watermelon can also be eaten, although the shells are tough and are usually removed or cracked. Seedless fruits have only soft, white, empty seed coats.

The watermelon is native to Africa, and wild relatives grow in the Kalahari and other dry regions of southern Africa. Cultivation began very early. Seeds have been found in ancient Egyptian tombs from about 4,000 years ago, and the fruit spread through the Mediterranean, Middle East and India, reaching China by about the tenth century. Today China is by far the leading grower of watermelons, and seed-type varieties are grown in China, Iran, Nigeria and parts of Central Asia, where the seeds are a significant commodity.

Seeds of Citrullus have long been valued as food in several cultures. In China, roasted melon seeds called guazi are a traditional snack, particularly at the Lunar New Year, when they are cracked and eaten at family gatherings. In the Middle East and Iran, seeds of watermelon, pumpkin and sunflower are sold salted from street vendors and eaten at celebrations.

In West Africa, a closely related type of Citrullus known as egusi is grown mainly for its seeds, which are ground to thicken soups and stews in Nigeria and neighbouring countries. In more recent years, shelled watermelon seeds have turned up as a health-food ingredient and in trail mixes, sprouted forms, powders and snack products, and as a by-product of juice and fruit processing.

Roasted and salted in the shell, watermelon seeds are cracked open with the teeth like sunflower seeds. Hulled kernels are added to trail mixes, granola, bars, baked goods and salads, ground into flour or pressed into oil. They can be sprouted or ground into a paste or milk. In Chinese cuisine they appear in festival snacks and pastries, and in some regions, watermelon seed oil is used for cooking and cosmetic products.

Dried watermelon seed kernels are rich in protein and fat, mostly unsaturated, and supply magnesium, phosphorus, zinc, iron and B vitamins. The shelled kernel is much more nutritious than the whole seed, whose tough hull is mostly fibre and hard to digest. They are calorie dense, so a small handful goes a long way. Roasted salted seeds can add a lot of sodium. Whole seeds swallowed accidentally while eating the fruit generally pass through harmlessly.