... : Purple Sweet Potato Color, a pure natural and water soluble food color produced by our company, is extracted ... . The process is checking, washing, slicing, extracting, filtrating, purifying, concentrating, sterilizing(pur purple sweet potato color/natural food colouring ... information is as following: Echo WangHuBei Zixin Biological Technology Co.LtdTel:86-0714-3286924Fax:86-0714-3286919 Mob:86 ...