Red shiso leaves, or akashiso in Japanese, have reddish purple leaves with a distinct aroma. The shape of the leaves is similar to that of shiso leaves; an oval leaf with pointy edges.
Shiso leaves are naturally burgundy. The green shiso leaves you often find at Japanese restaurants are actually a variant of red shiso leaves.
The color of akashiso comes from a color matter of anthocyanin. Because this pigment changes to bright red when mixed with acid, red shiso leaves are used for adding color to pickled plums and ginger in Japan.
Akashiso can be salted or used for juice. To prepare, rinse the leaves thoroughly, rub them with salt, then squeeze out the excess water.