Recent research reveals that some varieties of mushrooms, when pressure-cooked, unleash an exponential increase of flavonoids and vitamin C compared to raw. How is this even possible given that most foods lose their nutrients when cooked?!?

Recent research reveals that some varieties of mushrooms, when pressure-cooked, unleash an exponential increase of flavonoids and vitamin C compared to raw. How is this even possible given that most foods lose their nutrients when cooked?!?
This recipe gets a concentrated mushroom flavor from the addition of dried mushrooms - try different types to completely change the flavor. To thicken the soup we went with potatoes instead of...