Preservative film and food color indicator from purple sweet potato

Abstract

The invention relates to a food preservation film and color indicator from purple sweet potato comprising purple sweet potato powder; in which the purple sweet potato powder is heat-treated in two stages including steaming and freeze-drying before grinding into powder; polyvinyl alcohol (PVA) powder; and glycerin; in which the purple sweet potato powder is gelatinized before being mixed with PVA powder and glycerin to obtain a film-forming mixture, shaped and heat-treated the film-forming mixture at a predetermined temperature and time to obtain a food preservation film and color indicator from purple sweet potato.