Which is the anti-nutritional factor present in tuber yam?
The tuber family is actually a part of the plant family. The characteristics of the tuber family is that they were grown underground & it has swollen underground stem. Potatoes, yam & sweet potatoes etc. are from the tuber family because they were grown underground & it has swollen underground stem.
Do Mexicans know the difference between a Sweet Potato and Yam As it seems impossible to get a sweet potato here in Mexico?
No, it is a both a root and a type of tuber that has tap roots. Another answer: Potato plants have no central tap root. They have regular roots with connected tubers. Those tubers are what farmers harvest and sell as what we call potatoes. However the yam plant, not to be confused with sweet potatoes, does have a tap root.