Why are tortilla chips treated with lime?

Answer 1

Traditionally it was a (relatively) easy way to get the hulls off of the corn. It is still done for many types of corn (traditional masa for tamales for one). According to the book Nourishing Traditions, which gives a recipe, treating with lime (the mineral lime, not the fruit) makes the vitamin B-3 bio-available. Relocated indigenous people and poor southern farmers in the US who relied on corn meal or grits not treated with lime developed skin sores, fatigue, and mental illness ("pellagra") due to B-3 deficiency.