Updated: May 9, 2019
In my last post, we learned what emulsions are and some of types of emulsions you can make. We learned about phospholipids and their properties as emulsifiers.
Lecithin is a phospholipid found in eggs and cell walls. It is an example of an emulsifying agent. Fats are also emulsifying agents. They are triglycerides: a glycerin molecule with three fatty acid chains. If you remove one of those chains, then you are left with a water-loving end and a fat-loving end, which makes for a great emulsifying agent. If you read monoglycerides or diglycerides on a food label, now you know they are to stabilize emulsions and foams.
Polysorbates are a class of emulsifiers, and they are often used in cosmetics to solubilize essential oils into water-based products. They are a water-loving molecule with a fatty acid attached. According to Culinary Reactions, "polysorbate 80 is used in ice cream to modify how the proteins coat the fat droplets...and polysorbate 60 is used in hot cocoa mix". The number following the name indicates the length of the fatty acid chain.
There are some who are purists when it comes to emulsions, particularly the fancy, traditional sauces that are made by emulsions, such as hollandaise and beurre blancs. But if you're like me, here are some shortcuts to making these amazing sauces without all the trouble:
When making mayonnaise and other emulsions, must recipes start by slowly adding the oil to the beaten yolks and mustard, with a little bit of acid. Once the emulsion begins to form, then you can add the oil and acid. Pro tip: start with a small amount of yesterday's mayo beaten into the egg yolks and mustard, then dump in the other ingredients.
Add 1/8 teaspoon of xanthan gum to any oil and water emulsion to prevent splitting.
When making hollandaise sauce, the eggs have to heated to stabilize the emulsion. Heat cause the proteins in the eggs to denature, unravel, and tangle together to allow the oil-loving parts to find the oil. If you over heat them, then they can become rubbery. The trick to cooking them long enough to kill any bacteria: add acid to the eggs. The acid prevents the eggs from getting rubbery until the temperature gets high (around 195 °F).