Sformati (Analyze a Recipe #2)
Is there thickening/setting/solidifying due to protein denaturation and coagulation?
The thickening agent is the eggs, which are beaten (or lightly agitated) and then heated. The heating of the eggs denatures the proteins in them. Since denaturation is always followed by coagulation, the mixture becomes firm as the proteins in the egg have their hydrophobic insides exposed and stick together to hide them.
What is the source of the protein?
The source of the protein is the whole egg, whole milk, and the parmesan cheese. The eggs are the main protein in the recipe.
What is the means of protein denaturation?
Protein denaturation permanently alters the structure of a protein by breaking the non-covalent interactions holding the structure together, and the individual proteins unravel. Methods of protein denaturation include heating, agitation, and addition of acid. The unfolded proteins now have their internal hydrophobic regions exposed, and multiple unfolded proteins aggregate together in a process called coagulation. The proteins in this recipe begin to get denatured when the eggs are lightly beaten, or agitated. Following that the eggs are heated, this is when the majority of the denaturation occurs.
Is the protein diluted?
When a protein is diluted it impacts the level of heat needed to denature it. The more a protein is diluted the higher the temperature needed to denature it will be. The protein in this recipe is diluted prior to being heated. Cream, milk, soffritto, parmesan, and vegetables and herbs are all added to the eggs.
How is the dilution impacting coagulation and therefore the final texture of the cooked product?
The dilution of the egg proteins interferes with the processes of denaturation and coagulation. The sformati is cooked with steam in order to keep the baking temperature constant and prevent the egg proteins from coagulating too quickly and forcing out the diluting ingredients from the mixture (curdling).
Is there thickening/setting/solidifying due to gelation of starch?
No, there is no starch in this recipe. The thickening is done by protein denaturation and coagulation.
Is there a mixing of fat and water phases?
Yes, the cream, cheese, and olive oil contain fat phases, while the vegetables contain water phases. The milk and the eggs contain both fat and water phases.
What are the sources of the fat and the water?
The sources of fat include the egg yolks, cream, milk, cheese, and olive oil. The sources of water are the egg whites and the vegetables.
Is there emulsification of the two phases?
Yes, the custard is emulsified by the addition of the amphiphilic eggs. The milk in the custard is also an emulsion in and of itself.
How can you tell?
We can tell because all of these ingredients that contain water and fat phases combine to form a smooth custard. If the dish was not emulsified, you would see a layer of fat phase ingredients sitting on top of a layer of water phase ingredients – this would result in the custard weeping.
What is the emulsifier?
In the Sformati recipe the primary emulsifier are the eggs. Eggs are amphiphilic, meaning they have polar and non-polar regions and are able to interact with both water-based and fat-based ingredients. They contain lecithin, an emulsifying phospholipid. Additionally, milk is an emulsion. The process of homogenization makes it a much more stable emulsion by making all the milk fat globules around the same size and by coating them all partially in casein.