Fruit puree comes from processing the pulp of fruit. It can be substituted for refined sugar in baking because it contains fructose, the natural sugar occurring in fruit. Purees retain the flavor, color and aroma of the fruit from which they come and add bulk with fiber. Since they also contain water, it's important to reduce the liquid in a recipe by 1/4 cup whenever replacing sugar with puree. One cup or 8 ounces of fruit puree equals 1 to 2 tablespoons of sugar, depending on how sweet you want the recipe.
Match the Flavor
Fruit purees work best in recipes such as carrot cake and banana bread that have a fruit or vegetable ingredient. Matching the flavor of the fruit from which the puree comes is the best way to add the puree to a recipe. For example, with banana bread mashed ripe bananas can be substituted for refined sugar while maintaining the desired flavor. One medium ripe banana yields about 6 to 8 ounces of puree when mashed.
Apples must be cooked to make puree, or applesauce. Applesauce can be used in cakes, muffins and quick breads as a sugar substitute. The best apples for puree are those with a mild flavor, such as Gala and Red Delicious. Avoid using tart apples such as Granny Smith. To make 1 cup of unsweetened applesauce, wash, peel, core and slice 2 medium apples and cook at medium heat for 25 minutes. Allow the apples to cool slightly and mash them with a potato masher. If you want the applesauce to be smoother, puree them further in a blender.
Tropical fruit such as papaya make unusual puree for cakes and muffins. To make papaya puree, wash, rinse and dry a medium fruit. Remove the peel with a vegetable peeler. Slice the papaya in half lengthwise and scoop out the seeds with a spoon. Rinse each half with water to make sure all the seeds are out. Then scoop out the flesh and puree in a blender. A papaya gives 10 ounces of puree, or enough to substitute for as much as 2 tablespoons of sugar in a recipe.
Sometimes There's No Substitute
In some cases fruit puree can't be substituted for sugar in a recipe because of sugar's essential role in the chemical processes of baking. Sugar stabilizes egg whites, makes golden crusts for cakes, and attracts moisture that keeps baked goods fresh. Fruit purees can't perform any of these functions. Before you substitute fruit puree with sugar, you need to understand how the sugar works in a recipe.