What is this purple liquid?

Always enjoy exploring the food & beverages that Donki offers; ready-to-eat meals and wide range of interesting beverages.

What I tried from Donki’s Japan Mobile Food section was Purple Sweet Potato Latte that uses hokkaido milk and purple sweet potato powder from Japan. The texture was thick & creamy, definitely not a thirst quenching drink but love that interesting flavour.
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Purple Sweet Potato Latte (Iced) $3.20