. In
yellow or orange sweet potato species, carotenoids(such as β-
carotene) act as the primary pigment molecule [3] as well as
the source of provitaminA,which shows vitaminAactivity [4].
Carotenoids have strong antioxidant capacity to scavenge free
radicals because of their conjugated double bonds[5].
Generally,sweet potato is cooked, either by boiling,steaming or roasting, before consumption. Such thermal processing
can cause impairment of the functional compounds of sweet
potato.There have been reports of negative correlation between
heat treatments(steaming and baking) and some bioactive substances, such as anthocyanins. Carvalho et al. [6] reported
a dramatic decrease in both total carotenoid and β-carotene
contents ofsweet cassava after cooking.