Ketose sugars are a type of monosaccharide, or simple sugar, which has a free ketone group within it's chemistry. These sugars are some of the easiest for a body to absorb and digest and is also the sweetest of the sugars. These sugars are not very healthy to consume on a regular basis, so it is good to know what types of sugar ingredients contain these Ketose sugars so they can be consumed sparingly.
Dihydroxyacetone is an example of a Ketose sugar. It has a free Ketone (represented in chemistry diagrams as C=O) and CH2 molecules bonded with Hydrogen and Oxygen molecules on either side. This is an incredibly simple ketose sugar and is often as an ingredient where only a small, basic amount of sugar is needed for taste.
Ribulose has it's free ketone as the center of it's make-up, with hydrogen, carbon and oxygen molecules bonded on one side of it's diagram and carbon and oxygen and CH2 molecules bonded on the other side. This ketose sugar is a bit more complex, but is still used for basic sugar flavoring in certain foods.
Xylulose is another ketose sugar which is almost identical to ribulose, except for the fact that it is missing an oxygen molecule, which changes the make-up and consistency of the sugar entirely. Xylulose also works as a natural carbohydrate.
The most well-known and widely consumed of all the ketose sugars, fructose is the sweetest of all sugars in general and the most complex of the fructose sugars, as it has all the elements of the aforementioned ketose sugars combined in it. Fructose is made in a syrupy form in many cases which is better known as high fructose corn syrup and is in many candies, soft drinks and fast foods.