On an otherwise unadorned table at an event space overlooking Hong Kong’s Victoria Harbour, glass bowls displayed the constituent parts of the Impossible Burger. One contained a B-vitamin-laced potato protein paste, another wheat protein, a third a globule of coconut oil. In a fourth, shimmering crimson under the ceiling lights, was the secret sauce: heme (or haem), a component of many proteins, including hemoglobin — the pigment that gives blood its color. It’s also found in the roots of the soybean plant, which is where Impossible Foods extracts it from.