Emulsifiers are substances used in baking to give foods, including cakes, the proper texture. Common cake emulsifiers include monoglycerides, polygycerol esters, lactic acid esters, and polysorbates. Additional emulsifiers may include monoglycerides, polypylene glycol monsearate (PGME), and acetylated mono glycerides. A commonly found and natural substance called lecithin is also added to cake batters by many bakers. Depending on the kind of emulsifier, a cake has a certain consistency, thickness, and crumb softness; the product will also last longer with the addition of these key ingredients.
Liquid droplets suspended in another liquid, such as an oily compound with fat droplets, are the basis for emulsifiers. Cake emulsifiers consist of molecules that allow oil and water to mix, so oily fat and water in cake batter can be thoroughly mixed to get a desired quality for the finished product. The monoglycerides, lactic acid esters, and polysorbates that are used as cake emulsifiers help stabilize the foam structure of cake batter. They also allow the expansion of air cells, increasing the volume of the cake. Monoglycerides are starch preservatives found in beta crystal form, which is suitable for creating layers in the cake, and alpha crystal form which is more flexible and better suited for cakes that undergo heating.
Proper aeration of a cake is one of the ways quality is determined. Polyglycerol esters and PGMS are known as alpha tending cake emulsifiers, and mix well to allow for the desired amount of and size of bubbles in the cake batter. They also allow these bubbles to remain stable while the batter expands during baking, and keep starch from degrading to prevent the cake from becoming stale before it is eaten. When using polyglycerol esters and monoglycerides, the proportion of each can be adjusted to alter the fat content of the cake. High or low fat batters can feature the same kind of consistency when the ratio is carefully monitored.
There are a few factors that go into choosing from the varieties of cake emulsifiers. One is expense versus how well the emulsifier works, and if clean up time is added to the process then it might not be cost-effective to use. Lesser amounts are used for low-fat cakes, while local regulations can affect which emulsifiers are chosen. The demand for natural products can also limit which ones are selected, which is why lecithin is often preferred by bakers, and is also less straining on baking machinery.