I know normally when you want to buy bananas you will keep checking till you get the freshest one amongst others. No one will like to take those ones with dark patches and colouration. But hey, based on the nutritional values, research has proved it that that banana with black patches all over it's body is far more healthier than the the normal fresh one.
NOW SEE WHY.
according to the latest japanese research, a full ripe banana with dark patches on they yellow skin produces a substance called TUMOR NECROSIS FACTOR (TNF) which has the ability to combat abnormal cells.
The more darker patches it has the higher it's immunity enhancement quality. Hence the riper the banana the Better the anti-cancer quality. A yellow skin banana with dark spots on it is 8x more effective in enhancing the property of white blood cells than a green skin type.
So after reading this, no more freshness when choosing a banana but how much dark spots/patches it has on it's body.
SOURCE:GOZIEHEALTH