Are red apples more acidic than green?

The vitamin profile for red, green and yellow are similar. What will make the vitamin content vary will be things such as when it is picked, how it is stored, growing conditions, how it is prepared, with or without skin, etc. A sidenote: the nutrient profile of Apples is pretty low -- a medium Apple has 8 mg vitamin C, 5 mcg folate, etc. Apples are a decent source of fiber -- medium Apple has 4 - 5 grams (with skin) and it also has a nice phytochemical profile -- quercitin, zeaxanthin and beta carotene.