|Roots of yacón|
(Poeppig and Endlicher) H. Robinson
Polymnia sonchifolia Poeppig and Endlicher
The yacón (Smallanthus sonchifolius, syn.: Polymnia edulis, P. sonchifolia) is a perennial plant traditionally grown in the Northern and Central Andes from Colombia to Northern Argentina for its crisp, sweet-tasting tuberous roots. The texture and flavour are very similar to jicama, mainly differing in that yacón has some slightly sweet resinous and floral (similar to violet) undertones to its flavor. This flavoring is probably due to a sweet substance called inulin, as replicates the sweet taste found in the roots of elecampane, which also contains this substance. Another name for the yacón is Peruvian ground apple. The tuber is composed mostly of water and fructooligosaccharides.
Commonly called "jicama" in Ecuador, yacón is sometimes confused with that unrelated plant. Yacón is actually a close relative of the sunflower and Jerusalem artichoke. The plants produce a perennial rhizome to which the edible succulent storage roots are attached, the principal economic product of the plant. The rhizome develops just under the soil surface and produces continuously the aerial shoots. Dry and/or cold seasons cause the aerial shoots to die back, but the plant re-sprouts from the rhizome in favourable conditions of temperature and moisture. The edible storage tubers are large and typically weigh a few hundred grams to one kilogram.
These edible tubers contain fructooligosaccharides, an indigestible polysaccharide made up of fructose. Fructooligosaccharides taste sweet, but pass the human digestive tract unmetabolised and hence have very low caloric value. Moreover, fructooligosaccharides have prebiotic effect, meaning that they are used by "friendly" bacteria that favor colon health and digestion.
Yacón plants can grow to over 2 meters in height and produce small, yellow inconspicuous flowers at the end of the growing season. Unlike many other root vegetables domesticated by the indigenous peoples of the Andes (ulluco, oca) and mashua, yacón is not photoperiod sensitive, and can produce a commercial yield also in the subtropics.
Yacón storage roots are traditionally grown by farmers at mid-elevations in the eastern slopes of the Andes that descend toward the Amazon. Yacón is grown occasionally along field borders where the juicy roots provide a welcome source of refreshment during field work. Until as late as the early 2000s, yacón was hardly known outside of its limited native range, and was not available from urban markets; however, press reports of its use in Japan for its purported anti-hyperglycemic properties made the crop more widely known in Lima and other Peruvian cities. Companies have also developed novel products such as yacón syrup and yacón tea. Both products are popular among diabetic people and dieters.
Yacón can easily be grown in home gardens in climates with only gentle frosts. It grows well in southern Australia (including Tasmania) and New Zealand, where the climate is mild and the growing season long. The plant was introduced to Japan in the 1980s, and from there spread into other Asian countries, notably South Korea, China, the Philippines, and is now widely available in markets in these countries. Yacón has also recently been introduced into farmers' markets and natural food stores in the United States.
Propagation roots with growing points can be planted in a well-dug bed in early spring, near the time of the last expected frost. While aerial parts are damaged by frost, the roots are not harmed unless they freeze solid. Yacón is a vigorous grower much like Jerusalem artichokes. The plants grow best with fertilization.
After the first few frosts the tops will die and the plants are ready for harvest. It is generally best to leave some in the ground for propagating the following spring. Alternatively, the propagating roots can be kept in the refrigerator or buried away from frost until spring. While usable-sized tubers develop fairly early, they taste much sweeter after some frost.
In colonial times yacón consumption was identified with a Catholic religious celebration held at the time of an earlier Inca feast. In the Moche era, it may have been food for a special occasion. Effigies of edible food may have been placed at Moche burials for the nourishment of the dead, as offerings to lords of the other world, or in commemoration of a certain occasion. Moche depicted these yacón in their ceramics.
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