Purple Sweet Potato

Purple sweet potatoes, particularly varieties like Okinawan or Ayamurasaki, are grown in regions like China, Japan, and the U.S., where cool temperatures promote high anthocyanin content. These tubers develop intense violet colors that are naturally water-soluble.

After harvest, the potatoes are steamed or blanched to deactivate enzymes, then sliced and processed using water-based extraction. The liquid is filtered, concentrated, and often spray-dried into powders or standardized as liquid extracts. The pigments—mainly anthocyanins—are sensitive to light and heat but show reasonable stability under acidic conditions. Controlled drying and storage are key to preserving the color’s intensity and vibrancy.