Science of Grandma’s Ham and Spinach Quiche

Introduction:

Our recipe is called ‘Grandma’s Ham and Spinach Quiche’ because Anika’s grandmother created the recipe when her children were young. There was a family reunion where they were having breakfast foods. Everyone had to bring a different dish, and Anika’s grandmother brought the quiche. Since spinach and ham are not common in India, this Western dish was extremely popular amongst the family. Because of its success, Anika’s grandmother continued to make her famous quiche for special family get-togethers. Quiche is also one of Julia’s favorite foods because she would eat Quiche Lorraine with her grandmother who was also named Lorraine. Since we both have good memories associated with quiche and our grandmothers, we decided to go with Anika’s family recipe.

Scientific Content:

In our original recipe, we use whole eggs. The egg yolk is made up of 50% water, 34% fat, 16% protein while the egg whites are made up of 88% water, 0.2 % fat, 11% protein (West). Egg whites are high in protein but low in cholesterol and fat. However, as Spritzler states, this means they are also low in the other nutrients that are present in egg yolks like vitamins and minerals. As the Science of Eggs: Egg Science states, protein coagulation is when the structure of proteins is changed due to heat, mechanical action, or acids. In our recipe, the eggs undergo protein coagulation due to heat. The proteins form a gel (a liquid dispersed throughout a continuous solid), with the dispersed phase being half & half and the proteins being the continuous phase. Below is a table showing the processes of protein coagulation at certain temperatures.

Eggs can be used in recipes in multiple ways. When heated, the egg proteins move faster and bump into each other. This causes the bonds that keep the proteins “curled up” to break and allows new bonds to be formed. These new bonds connect the different proteins together, which created a network. If eggs are cooked too long, this network becomes too solid, giving your eggs a rubbery taste (Science of Eggs: Egg Science).

When whipped, eggs create a foam. By adding air bubbles to eggs, it causes the proteins to denature similarly to how adding heat does. The proteins in egg whites contain both hydrophobic (water-hating) and hydrophilic (water-loving) amino acids. Before an egg protein is denatured, the hydrophobic acids are on the inside surrounded by the hydrophilic acids. The hydrophilic acids are attracted to the water they are in. Once air is added to the mix, the protein uncurls so the hydrophobic acids can bond with the air, and the hydrophilic acids can bond with the water. This creates a network that includes water, proteins, and air (Science of Eggs: Egg Science).

One of the ways to help water and oil mix is to use an emulsifier. Egg yolk is a good emulsifier because of its hydrophobic and hydrophilic amino acids. When water, oil, and egg yolk are mixed, the hydrophobic amino acids in the egg yolk will bond to the oil while the hydrophilic amino acids in the egg yolk will bond to the water. Another reason egg yolks are good emulsifiers is because they contain a phospholipid called lecithin. Lecethin is a “fatlike molecule with a water-loving ‘head’ and a long, water-loving ‘tail'” (Science of Eggs: Egg Science).

Custards generally have a ratio of 4:1 liquid to egg (Quiche: A Custard Pie). When custards are baking, they are unstirred, allowing the ingredients to set into a solid gel. The consistency of your end result depends on the number of egg whites and egg yolks you use. More egg whites produce a firmer result, while more egg yolks make the end result creamier (Science of Eggs: Egg Science).

When half  & half is added to the eggs this will dilute the egg proteins, and produces a more tender product with less coagulation. Half & half is a combination of equal parts milk and cream. It contains between 10-18% fat, instead of the at least 36% fat that heavy cream has (Alfaro). This recipe uses half & half to get a creamy consistency without too much fat and richness. Recipes in general use cream or half & half over regular milk because of the fat content. Since there is more fat, it can be heated to a higher temperature without curdling (Alfaro).

For the type of heat energy used to cook the quiche, you would use convection heat energy. This is because the quiche is cooked in an oven, and ovens use convection heat. The way convection ovens produce heat is by increasing the rate of heat transfer. This is done by using fans to start air movement (Potter).

Recipe Adjustment:

To make this quiche healthier, you can change the number of eggs. Instead of using 3 large eggs, you can use 1 large egg and 4 egg whites. You need four egg whites instead of just 2 in order to keep the volume of eggs in the recipe the same. By using egg whites, this recipe will have fewer calories and cholesterol. However, using egg whites will produce a firmer quiche. 

When looking at eggs, most of the protein comes from the egg whites. According to West, “Egg whites are high in protein but low in calories. In fact, they pack around 67% of all the protein found in eggs. This protein is high-quality and complete, meaning it contains all nine essential amino acids in the amounts your body needs to function at its best.”