Tuna (prickly pear): what it is, history and varieties of the nopal fruit

What is it?

The tuna (prickly pear) is the fleshy fruit of the nopal, a cactus endemic to Mexico and a sacred plant of Mexican culture. It is an oval berry five to ten centimetres long, covered with small fine spines called glochids, with a thick skin of green, yellow, red, purple or white colour according to the variety, and fleshy, sweet pulp full of small edible seeds. It is one of the most important traditional fruits of the Mexican highlands and is traditionally eaten fresh, peeled on the spot and eaten with a spoon or the hands, as well as in agua fresca de tuna, ice creams, lollies, jams, queso de tuna (a concentrated sweet), aguamiel and melcocha. Its main season runs from June to October, when the street stalls of central Mexico, markets and carts fill with the sweet aroma and colourful presence of this fruit. Mexico is the world's leading producer of tuna.

Origin and history

The tuna and the nopal form part of the founding symbolism of Mexico: the national coat of arms shows an eagle perched on a nopal devouring a serpent, an image taken from the myth of the founding of Tenochtitlan by the Mexica in 1325, where the god Huitzilopochtli ordered them to settle where they found this symbol. The word tuna comes from the Antillean Taíno, the language the Spanish brought from the Caribbean; the Nahua called it nochtli, a word that survives in place names such as Tenochtitlan (place of the tunas that grow on the stones). The nopal, a plant of the genus Opuntia, is endemic to North America and was domesticated in central Mexico at least 9,000 years ago, according to archaeological evidence from the Tehuacán valley. Sahagún in his General History of the Things of New Spain and Francisco Hernández in his Natural History of New Spain (16th century) amply document its dietary, medicinal and ritual uses. After the Conquest, the nopal was taken to Europe, Africa and other parts of the Americas, naturalising in Mediterranean climates. The modern Mexican tuna industry is centred in states such as Hidalgo, Zacatecas, San Luis Potosí, the State of Mexico and Puebla, with the region of San Martín de las Pirámides as one of the most celebrated producers. CONABIO documents Opuntia ficus-indica among the most widespread and domesticated cacti in the world.

Characteristic ingredients

The main domesticated species is Opuntia ficus-indica, though there are other cultivated species such as Opuntia streptacantha, Opuntia robusta and Opuntia megacantha, all giving tunas of different colours and flavours. The most commercial varieties are: white or reina tuna, with green-white pulp, soft and very sweet, considered the best quality; red or cardona tuna, with intensely red pulp, slightly tart and very aromatic; yellow or burrona tuna, large and sweet; purple tuna, sweet with strawberry notes; and Castilla tuna, elongated. The glochids or fine spines are traditionally removed by burning them over fire or brushing them off; in markets, the tunas are sold already brushed or peeled. The seeds are edible, though some people discard them. The pulp contains high levels of vitamin C, magnesium, calcium and antioxidants, especially betalains in the red varieties. In Mexican cooking, the tuna is used fresh, but it is also transformed into agua fresca, sorbets, ice creams, queso de tuna (a solid sweet made by reduction), melcocha, jam, and fermented drinks such as colonche (a traditional red-tuna wine typical of Zacatecas and San Luis Potosí). The xoconostle, considered a type of tart tuna, is treated separately for its distinct culinary uses in stews and salsas.

Cultural significance

The tuna is a national symbol of Mexico and a millennia-old biocultural heritage. Its presence on the National Coat of Arms, on the flag and in the popular imagination makes it one of the most representative plants of the country. The cultivation of the nopal and the harvest of the tuna sustain thousands of small rural producers in central and northern Mexico, especially in Hidalgo, Zacatecas, San Luis Potosí, the State of Mexico and Puebla, where there are annual fairs such as the National Tuna Fair in San Martín de las Pirámides (State of Mexico). Traditional Mexican Cuisine, declared an Intangible Cultural Heritage of Humanity by UNESCO in 2010, includes the tuna and the nopal among its pillars. Economically, Mexico produces more than 50% of the world's tuna, with exports to the United States, Europe and Asia. The nopal and the tuna are key crops for food security in semi-arid areas, since they require little water and adapt to poor soils. Mexican researchers have developed new varieties and industrial applications, from natural colourings to bioplastics, food supplements and cosmetics, positioning the tuna as a crop of the future in the face of climate change.

Frequently asked questions

What is the difference between tuna and xoconostle?

Both are fruits of the genus Opuntia, but the common tuna (Opuntia ficus-indica) is sweet and eaten as a dessert fruit or in drinks. The xoconostle (Opuntia matudae or joconostle) is markedly tart, with pulp of pinkish tones and seeds concentrated in the centre, and is used mainly in savoury cooking: salsas, stews such as mole de olla and preserves such as xoconostle in syrup.

What does the tuna taste like?

The pulp is juicy, refreshing and sweet, with a mild floral flavour reminiscent of a cross between watermelon, pear and kiwi. The white variety is the sweetest and most delicate; the red one is slightly more tart with notes of strawberry or raspberry. The texture is similar to that of a ripe melon, dotted with small crunchy seeds that are eaten along with the pulp or discarded when chewing.

How is the tuna served?

It is generally served peeled and cut into halves or slices, on a plate or in a glass with a squeeze of lime and optional salt or tajín. It is also blended with water and sugar to make agua fresca de tuna, prepared as a sorbet or lolly, made into jam or queso de tuna, and in Zacatecas it is fermented to make colonche. To peel it, a knife is used and care is taken with the glochids.

Where does the tuna come from?

The tuna is native to Mexico, where the nopal (Opuntia spp.) was domesticated at least 9,000 years ago in the Tehuacán-Cuicatlán valley. Its cultivation and consumption are documented from pre-Hispanic times in sources such as those of Sahagún and Francisco Hernández. After the Conquest it spread around the world, naturalising in the Mediterranean, Africa and other parts of the Americas. Today Mexico is the world's leading producer.