Black rice

Black rice is not a separate species but a group of Oryza sativa varieties whose outer bran layer is deep purple-black because of anthocyanin pigments, the same family that colours blueberries and blackcurrants. The grains look black when dry and are usually sold unhulled or lightly milled.

Cooked, the rice is chewy and slightly sticky, with a nutty, faintly sweet flavour, and it stains the cooking water and other food a deep purple.

Types include glutinous black rice used in desserts in Southeast Asia, and non-glutinous types, such as Chinese forbidden rice, and Indian chak-hao from Manipur.

Black rice originated in Asia, with documented traditions in China and Northeast India, and it is thought to arise from the long selection of pigmented rice varieties within the broader domestication of rice that began in the Yangtze valley, probably more than eight thousand years ago.

Pigmented rice was grown in many regions of Asia, including Indonesia, Thailand, Vietnam, Korea and Japan.

The word rice comes via Old French and Italian from Latin oriza and Greek oryza, which probably came from an Indo-Iranian word of Asian origin.

A widely repeated story says black rice was reserved for the Chinese emperor and his court, grown as a tribute and forbidden to commoners, which is how the name forbidden rice arose. The story is hard to verify in the historical record, but the name was popularised in the 21st century by an American importer, and the rice itself has long been associated with medicine and prestige in China.

In Manipur in northeast India, chak-hao is served at feasts and in a sweet pudding known as chak-hao kheer and had a role in rituals. In Indonesia, Thailand and Bali, black glutinous rice is used in desserts such as bubur injin and khao niao dam.

Throughout Asia, pigmented rice was displaced by white rice and high-yield varieties, but it has been revived as a niche product, and researchers have identified the genetic change responsible for its black colour.

In the early 2000s, publications on the antioxidant content of black rice bran raised its profile in Western markets.

Black rice is cooked like brown rice, by simmering in water for about thirty to forty-five minutes, and served as a side, in salads and grain bowls, or as a base for sushi-like rolls. Glutinous types are made into sweet porridges and puddings with coconut milk, and are used in dessert sticky rice.

Black rice flour is used in noodles, breads and cakes, which turn a purple colour. The bran is sold as a natural food colouring.

Fermented black rice is made into vinegar and rice wine in parts of Asia, and a purple colour is used in Japanese and Korean cooking.

The dark bran of black rice has higher levels of anthocyanins, other phenolic compounds and fibre than white rice, and has stronger antioxidant activity in laboratory tests. Whole-grain forms are linked more generally with better blood sugar control and heart health than refined rice in population studies.

Direct clinical evidence for black rice itself is limited and mostly from small studies.