CHEESE IS NOT just food, it’s a variety show. The multitude of aromas, flavors, and textures found in cheeses throughout the world is more than we encounter with any other food. It comes in hundreds of varieties; even within a variety, differences are noticeable. And it’s a food that provides nutrition in the form of vitamins, minerals, and a high-quality source of protein that can be kept for months.
The science behind the transformation from plants to milk to cheese is amazing. In fact, cheese has much in common with wine and beer: They result from fermentation by microorganisms; they are “value-added” products where processing greatly increases the value; and they reflect local climate and terrain. Cheese has fascinated humanity for a long time, inspiring people to refer to it as everything from “the wine of foods” The production of cheese predates recorded history. Its origin is assumed to lie in the practice of transporting milk in bladders made of ruminants' stomachs, with their inherent supply of rennet. There is no conclusive evidence indicating where cheese-making originated, either in Europe, Central Asia, the Middle East, or Sahara. Cheese-making was known in Europe at the earliest level of Hellenic myth and, according to Pliny the Elder, had become a sophisticated enterprise by the time ancient Rome came into being, when valued foreign cheeses were transported to Rome to satisfy the tastes of the social elite.
The most basic principle of making cheese is to put the acid such as lemon and vinegar in milk to quickly solidify. Unlike eggs or meat, milk does not change much when heated. It's because milk contains a lot of casein protein compared to other meats. Casein does not clot when it is heated, but acidity hardens like a jelly. In milk, casein is four times more than other proteins.
WHY IS CHEESE YELLOW?
Studies have shown that color — more so than labeling and even actual taste — affects our expectations and perceptions of food flavor, and cheese is no exception. Even though the fat contents and flavors in orange and yellow cheddar are identical, some people perceive the former to be richer than the latter.
Annatto is what gives cheese an orange or more pronounced yellow color. It comes from the achiote (Bixa orellana) tree found in Mexico, the Caribbean, and the western portion of South America. Annatto’s major component bixin and much of its molecular structure is similar to that of β-carotene, the compound that gives carrots their orange color. Cows transfer carotenoids (β-carotene and related compounds) from their diet to the milk, where they bind to the fat. This yellow color is not visible since the fat content of milk is less than 4% and the carotenoid concentration less than 0.1%, and the fat globules are surrounded by casein. But most of the whey is lost during cheesemaking, causing the fat and carotenoid contents to increase, and the casein network to loosen up — revealing the fat so the resulting cheese takes on a yellow color.
Goats, sheep, and water buffalo do not pass carotenoids to milk (converting it to vitamin A instead), so their cheese is white. The additive for white cheese such as mozzarella is titanium dioxide — a mineral commonly added to toothpaste — which masks color. Other cheese additives that bleach color are hydrogen peroxide and benzoyl peroxide.
CAN YOU MAKE CHEESE FROM HUMAN BREAST MILK?
That is the strangest question I have ever been asked about cheese — and it’s been asked several times. Breast-feeding mothers often have milk left over, and people sometimes wonder what can be done with it. Perhaps make some sort of cheese from it?
But the answer is no, because the milk won’t coagulate properly. Breast milk alone can’t be made into cheese because it contains too little protein (only 1%), and only some of the protein is casein. In early lactation, 90% of the proteins are whey proteins, decreasing to 50% in late lactation. Research in our laboratory some years ago demonstrated that human milk will not form a curd.
Joohee Lee
