I'm looking at a bottle of Hawaiian Punch. Its flavor is listed as "Grape Geyser." It contains:
Water
High fructose corn syrup
Concentrated juices (pineapple, grape, apple, pear and passionfruit)
Purees (papaya and guava)
Citric acid
Natural and artificial flavors
Pectin
Red #40
Blue #1
Sodium hexametaphosphate
Potassium sorbate
Sodium benzoate
Ascorbic acid
And for all of that, it still taste nothing like grapes, or grape juice. Its flavor most closely resembles that of grape chewing gum. Yummy.