INGREDIENTS - Fat Emulsions

Most bakery ingredients mix easily with water and other liquids and actually undergo a change in form. For example, salt and sugar dissolve in water; flour and starch absorb water and the water becomes bound up with the starch and protein molecules. Fat, on the other hand, does not change form when it is mixed with liquids or other bakery ingredients. Instead, it is merely broken down into smaller and smaller particles during mixing.These small fat particles eventually become more or less evenly distributed in the mix. A uniform mixture of two unmixable substances,such as a fat and water,is called an emulsion. Mayonnaise is a familiar example of an emulsion from outside the bakeshop—in this case, an emulsion of oil and vinegar.There are also emulsions of air and fat,such as that formed when shortening and sugar are creamed together in the production of cakes and other products. Fats have differing abilities to form emulsions. For example, if the wrong shortening is used in certain cakes, the emulsion may fail because the batter contains more water than the fat can hold.We then say that the batter curdles or breaks.