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Oca (Oxalis tuberosa Molina) is variously known in English as oca or oxalis; in the Andean languages Quechua  as uqa, ok'a,  () and Aymara as apilla . In Spanish, it is variously known as oca (in Peru and Ecuador);oca, ibia, hibia, huasisai, or ibi (in Colombia); ruba, timbo, quiba, macachin or miquichi (in Venezuela); and papa roja, papa colorada, papa extranjera (in Mexico).


O. tuberosa is a perennial herbaceous plant that is erect in the early stages of development but becomes prostrate later as it matures. It is cultivated for its edible crunchy root in which the plant stores starch over the winter or cold periods when it is not growing.  Oca is vegetatively propagated from cuttings or its tubers. The tubers are elliptical or cylindrical in shape, with the colours including white, yellow, red and purple. The length of the tuber is about 5 to 7.5 cm and the diameter about 2.5 to 3.75 cm.

Oca is one of the traditional tubers of the Andes and together with ullucu (Ullucus tuberosus), mashwa (Tropaeolum tuberosum) and native potatoes (Solanum spp.) is an important source of dietary energy in this region.  Oca does well at the higher latitudes as it requires a long growing season, and forms tubers when the day length shortens in the fall. However, in areas with harsh winter climates, the cold weather that accompanies shorter days may kill the plant before tubers have a chance to form.

Similar to other root and tuber crops of the region, oca is eaten boiled, baked or fried. In the Andes, it is consumed in stews and soups, or can be served as a sweet. In Mexico, it is eaten raw with salt, lemon and hot pepper. It can also be first sun-dried to make it sweeter and then parboiled or roasted, or ground into flour for use in porridges and desserts.

Where it originated

The likely origin and centre of diversity for oca is in the highlands of the Andes, from Colombia to Argentina, and especially important in Peru and Bolivia. Its many wild relatives are also found in this region. In addition to being found commonly across South America and Mexico, it is also being widely grown in New Zealand, where it is known as the New Zealand yam.

How to eat it

Stir-fried spicy oca and potato (4 servings)

(adapted from http://plantlightly.com/2013/04/1685/)

Ingredients: 500 g oca; 500 g small firm potatoes, cut in halves or quarters; 2 red onions; sliced; 2 cloves crushed garlic; 2 sweet red pepper, sliced; fresh coriander leaves; grated rind of lemon; dried chilli flakes; crushed pink peppercorns; vegetable oil for frying.

Wash and clean the oca thoroughly. Leave the tubers whole. Pop the oca into hot water to blanch for a few minutes; this also helps to take out the bitterness. Don’t boil or leave the tubers in the water for too long, as they are a starchy vegetable and you don’t want to turn them into mush. Dry the oca and place on a baking tray. Wash and cut the small potatoes and add them to the tray. Chop the red pepper, but don’t cut them too small or they will disintegrate, and add to the tray. Add oil and sprinkle with pink peppercorns then place in an oven heated to 180 ºC for around 20 minutes. Shortly before the oca is taken out of the oven, fry the onion on a low heat to allow it to caramelize. When the oca is ready, transfer to a serving bowl and mix in the grated lemon peel, fried red onion, fresh coriander and dried chilli flakes to taste.


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