1. Which type of grape, purple in colour, is the predominant type used for grape juice in the US?
From Quiz Color Me Purple, Part 4: Eat Your Purples!
Answer:
Concord grape
Concord grapes are named after the town of Concord in Massachusetts. As well as grape juice, they are also used to make grape jam (if you're eating a PBJ, chances are the jam will have Concord grapes in it), wine - especially kosher wine - and grape-flavoured sweets. Concord grapes also contain methyl anthranilate, which is used as a flavouring agent because of its fruity grape smell.
Concord grapes are high in antioxidants, minerals and, vitamins (especially vitamins C and K), and compounds which help protect the eyes, such as lutein and zeaxanthin. They make a nice healthy snack as they're fairly easy to carry around (I often take a small bunch to work with me). Their high water content also helps keep you hydrated.2
[contributed by Kankurette]