Editing Meringue (section)

==Compound interactions==
There are three main ingredients in a meringue recipe that interact to form the foam structure: egg whites, sugar, and cream of tartar or acid. The backbone of the foam structure is made up of proteins, amino acid chains. Egg whites provide the meringue with necessary proteins that form the meringue foam. The proteins are originally oriented in a tangled ball but must be uncoiled into strands; this is referred to as denaturation. There are two ways a protein can be denatured: through physical or chemical process. When forming a meringue the egg whites are beat until the proteins are denatured—a physical process. Also by beating the egg whites, air is incorporated into the protein structure creating an air–water protein mixture interface. The friction from beating the eggs adds heat to the process, which causes the proteins to increase in elasticity. As the proteins are being stretched during the denaturation process they are also coagulating together forming a protein network. After the denaturation process the egg whites will become six to eight times their original size. If the proteins are beat for too long they will become stretched out too far and become too weak to support the foam structure.<ref>{{cite web |title=Food for Today |date=2017 |access-date=December 5, 2017 |url=https://highered.mheducation.com/sites/0078616441/student_view0/food_science_activities/demystifying_meringue.html |archive-date=January 19, 2018 |archive-url=https://web.archive.org/web/20180119214641/http://highered.mheducation.com/sites/0078616441/student_view0/food_science_activities/demystifying_meringue.html |url-status=live }}</ref>

[[Cream of tartar]], also known as potassium hydrogen tartrate, {{chem2|KC4H5O6}}, is added to the egg whites before the denaturation process. Cream of tartar is an [[acid]] that is used to help stabilize and coagulate the proteins, which aids in a stronger protein network to trap air for the foam formation. Cream of tartar has a low pH to help bring the proteins near their [[isoelectric point]] to allow them to be denatured easier. The isoelectric point is a specific pH where a molecule, in this case protein, has no net electrical charge. The electrical charge on a protein would normally hold the protein together in its coiled clump.<ref>{{cite web |title=Baffling Beaters |publisher=[[Institute of Food Technologists]] |access-date=December 2, 2017 |url=http://www.ift.org/~/media/Knowledge%20Center/Learn%20Food%20Sciene/Food%20Science%20Activity%20Guide/activity_bafflingbeaters.pdf}}</ref>

The cream of tartar also acts as a catalyst affecting the sugar structure. Sucrose is a disaccharide made up of [[glucose]] and [[fructose]]. Cream of tartar inverts the sugar during the baking process, meaning the molecule is split into two parts containing glucose and fructose. This prevents the sugar from recrystallizing and giving the meringue a gritty, undesirable texture.<ref>{{cite web |date=April 4, 2011 |title=Cream of tartar |access-date=December 2, 2017 |url=http://www.madfoodscience.com/post/4338474877/cream-of-tartar |work=MadFoodScience.com |archive-date=December 16, 2017 |archive-url=https://web.archive.org/web/20171216201144/http://www.madfoodscience.com/post/4338474877/cream-of-tartar |url-status=live }}</ref>

Sugar is the final ingredient that is used to help form and stabilize the foam structure. Sugar is [[hydrophilic]], extracting water out of the egg whites. This will lighten the protein network, allowing the foam to be stronger and more elastic. The sugar dissolves in the protein network but does not become part of the protein network. The sugar must be added slowly to the egg whites, while continuously mixing. If it is added all at once, it will not be evenly distributed, causing the protein network to collapse due to the weight of the sugar in one area of the meringue.<ref name="Demistifying">{{cite web |title=Demystifying Meringue |work=Food for Today |date=2017 |access-date=December 5, 2017 |url=https://highered.mheducation.com/sites/0078616441/student_view0/food_science_activities/demystifying_meringue.html |archive-date=January 19, 2018 |archive-url=https://web.archive.org/web/20180119214641/http://highered.mheducation.com/sites/0078616441/student_view0/food_science_activities/demystifying_meringue.html |url-status=live }}</ref>

After a strong protein network has formed a complete foam, the meringue is ready to be baked. Adding heat to the mixture is the final step to strengthen the foam structure. The meringue must be baked at a low temperature for a long period of time. This allows the proteins to finish coagulating, strengthening the meringue evenly throughout. If the proteins are not baked evenly, the bottom of the meringue will not be able to support the structural weight, causing the meringue to collapse. The heat causes the air bubbles to expand, creating an airier structure. The water in the structure evaporates, causing the meringue to become lighter with a stronger foam structure. It is important to not evaporate all of the water out of the meringue, as some water is necessary to hold the foam together.<ref name="Demistifying"/>