Shiitake mushrooms (Fig. 1) are rich in vitamin D, but there is a method to increase vitamin D of raw Shiitake mushrooms.
The method to increase vitamin D of raw Shiitake mushrooms is…
Leaving raw Shiitake mushrooms in the sun.
Shiitake mushrooms contain a substance called Ergosterol which turns into vitamin D by being exposed to UV. Vitamin D of Shiitake mushroom becomes more than tripled by leaving in the sun for 1 hour.
Generally raw Shiitake mushroom is grown in the dark place so that it is not left in the sun.
It is recommended to leave raw Shiitake mushroom in the sun for about 1 hour before cooking.
When you leave Shiitake mushrooms in the sun, it is more effective to face the back of cap of Shiitake mushrooms up to increase vitamin D (Fig. 2).