Dutch processed cocoa is Cacao solids that have been treated with an alkalizing agent to reduce the natural acidity of Cacao, giving it a less bitter taste and darker colour. It forms the basis for much of modern chocolate, and is used in ice cream, hot chocolate, and baking.
The Dutch process was developed in the early 19th century by Ducth chocolate maker Coenraad Johannes van Houten, whose father Casparus was responsible for the development of the method of removing fat from Cacao beans by hydraulic press around 1828, forming the basis for cocoa powder. These developments greatly expanded the use of cocoa, which had been mostly used as a beverage in Europe until that time.
To produce cocoa powder, Cacao beans are chemically processed and roasted, which destroys a large amount of the antioxidants and flavanols (compounds that keep you young and healthy). A recent study suggested that between 60% and 90% of the original antioxidants in Cacao are lost through Dutch processing.