Common Names: Sweet Potato, Sweetpotato, Yam, Batata, Boniato, Camote, Kumara

The Sweet Potato, belonging to the Morning Glory family (Convolvulaceae) and not related to potatoes, is native to the West Indies and Central America, although early reports of them in Indonesia and Philippines too. It is a vine-like, perennial herb but is cultivated as an annual. It is now grown in more than 100 countries in tropical, sub-tropical and temperate climates. It is one of only seven world food crops with an annual production of more than 100 million metric tons per year, and ranks thirteenth globally in production value among agricultural commodities. It is cultivated primarily for the enlarged edible storage roots, which provide high amounts of starch.

Although variation in storage root skin color and flesh color is abundant, there are two general types: a dry mealy flesh, and a moist, seedy type. In most developing countries, the root has white to cream-colored flesh and a bland, non-sweet flavor. In contrast, the type most used in developed countries has root flesh color of yellow or deep orange, a moist texture, a very distinct flavor, and high sugar content. This type is mistakenly referred to as “Yams” in the US, but the true yam is of the family Dioscorea.

Sweet Potatoes are a staple food of many peoples of the tropics, but in the industrialised world are principally a vegetable or a dessert. They are cooked, canned, frozen, dehydrated, and used as a source of flour, starch, glucose syrup and alcohol. Various products such as candy, pastas, flour, and drinks are produced in local industries. Both starchy roots and vines can be used as animal feed. Nutrients supplied include beta-carotene (a precursor of vitamin A), vitamin C, iron, potassium, calcium, and fibre. The moist orange-fleshed variety is high in beta carotene.

Sweet Potatoes contain trypsin inhibitors, which may reduce ability to utilize protein if eaten raw. However, trypsin inhibitors do not survive cooking and are of no consequence in cooked roots.

The starch is used commercially for sizing textiles and papers, for the manufacture of adhesives, and in laundries. In the U.S., large quantities of sweet potatoes, either freshly harvested or shredded and dried, are used as feed for livestock.

Allergens/Function:

A beta-amylase has been isolated. It showed 50-60% identity in the amino acid sequence with those of beta-amylases from soybean and barley, while it about 25% with those of three bacterial beta-amylases deduced from the cDNA sequences. (Toda 1993 ref.7016 3) It’s allergenic potential has not been evaluated.

Adverse Reactions:

IGE AND IMMUNE:
Allergic reactions.

IgE antibodies to sweet potato have been measured in children (Matsumaru 1992 ref.328 43) (Yamada 1992 ref.213 34) and in adults (Konatsu 1992 ref.214 34) using Pharmacia CAP System.

Other species of Ipomea are involved in allergic pollinosis. (Mondal 1998 ref.7017 3)

Infantile food protein-induced enterocolitis syndrome (FPIES) is a severe, cell-mediated gastrointestinal food hypersensitivity typically provoked by cow's milk or soy. This study reports on other foods causing this syndrome: 14 infants with FPIES caused by grains (rice, oat, and barley), vegetables (sweet potato, squash, string beans, peas), or poultry (chicken and turkey) were identified. Symptoms of typical FPIES are delayed (median: 2 hours) and include the onset of vomiting, diarrhea, and lethargy/dehydration. Eleven infants (78%) reacted to >1 food protein, including 7 (50%) that reacted to >1 grain. Nine (64%) of all patients with solid food-FPIES also had cow's milk and/or soy-FPIES. Initial presentation was severe in 79% of the patients, prompting sepsis evaluations (57%) and hospitalization (64%) for dehydration or shock. None of the patients developed FPIES to maternally ingested foods while breastfeeding unless the causal food was fed directly to the infant. (Nowak-Wegrzyn 2003 ref.7791 5)

NON IMMUNE:
Sweet potatoes contain phytoalexins that can cause lung edema and are hepatotoxic to mice. (Beier 1990 ref.1683 2)

Sweet potato may be infected with the mould, Fusarium solani, which produces a toxic substance, furanoterpenoid. (Parasakthy 1993 ref.7013 3)

See: Psoralens.