This special cooking method is much gentler on delicate vitamins than cooking in a regular pot. For example, up to 90% of vitamin C is retained during pressure cooking. Food also retains its natural color when cooked in a pressure cooker. The reason for this is that during the initial boil, the steam almost completely displaces the air inside the pressure cooker. Once the pressure valve is closed and the cooking process begins, there is hardly any oxygen left inside the pot, which is responsible for the degradation of valuable vitamins and nutrients. Food cooked under pressure is not only delicious but also visually appealing.