anthocyanins (also anthocyans; from greek: ("anthos") "flower" and / "kyaneos/kyanous" "dark blue") are water-soluble vacuolar pigments that, depending on their ph, may appear red, purple, blue or black. food plants rich in anthocyanins include the blueberry, raspberry, black rice, and black soybean, among many others that are red, blue, purple, or black. some of the colors of autumn leaves are derived from anthocyanins.