The Science Behind the Perfect Macaron
Name: Amanda Botts
Student #: 20617129
Class: BIOL 439
Dr. Bruce Greenberg
Macarons are a Parisian pastry consisting of a crisp shell and a spongey inside that melts in your mouth. Two meringue-based macaron cookies are typically sandwiched together with some type of filling in the middle. The various flavour and colour combinations are endless, from simple vanilla macarons with a basic vanilla buttercream to lavender infused macarons with a milky, sweet, golden honey filling. Though simple in presentation, the art and science of making macarons goes much beyond combining a few ingredients in a bowl and mixing with a wooden spoon. Macarons require egg whites whisked to the perfect peak, the exact amount of sugar, a precise measure of almond flour, and a folding technique specific to the prevention of complete deflation.
The Egg White
Egg whites are composed mostly of water (88%), proteins (11%), and a very low amount of carbohydrates and lipids (1%) (McGee, 2004). Of the egg white proteins, most are ovalbumin (54%) followed by ovotransferrin, ovomucoid, ovomucin, and lysozyme which combined make up 30% (McGee, 2004). When egg whites are beaten, some of the hydrogen bonds keeping the proteins structured denature, causing protein unfolding and exposure of hydrophobic protein elements (Hy & Hn, 2000). Egg whites are mainly composed of water; thus, this denaturing of proteins promotes protein-protein cross-linking in attempt to limit the exposure of hydrophobic protein elements to water and to also stabilize the air bubbles that are introduced to the egg whites by whisking (Foegeding, Luck, & Davis, 2006). The air interacts with the water already present in the egg whites and results in an overall increase in volume of 600-700% solely due to air bubbles (Foegeding, Luck, & Davis, 2006). The proteins form non-specific bonds in order to become stabilized, including ionic bonds and di-sulphide bridges, that change the structure of the proteins and form a stiff network (Rhodes, 2012). Friction from beating introduces heat which increases elasticity of the proteins, promoting coagulation and formation of a large protein matrix (Vega & Sanghvi, 2012). The egg whites will first form soft peaks which are defined by peaks that will droop when left alone, and then hard peaks which will stand tall as more proteins are denatured and more protein-protein bonds form (McGee, 2004). If beaten for too long however, overstretching of the proteins will occur, which will cause them to become weak, and the foam will deflate, resulting in a sad, unstructured mess that will become caked onto your baking sheet and essentially ruin it (Vega & Sanghvi, 2012).
The strength of the egg-white protein matrix can also be enhanced by the convention of beating the egg whites in a copper bowl (McGee, 2004). As the egg whites are beaten, tiny flecks of copper break off the bowl and are whisked into the egg mixture (Lawandi, 201...