Cheese-making is a long and complex process. It includes a number of biochemical reactions and is a great example of the importance of chemistry and biology in food preparation. Cheese making has been around for a long time and dates back possibly to when animals were first domesticated. The series of reactions that go into making good cheese need careful monitoring and control.
Cheese and Preservation
The main ingredient in cheese is milk. Cheese can be regarded as a means of preserving milk. Unlike milk, cheese can be kept for very long periods of time, which can be months or even years. The careful process used in the conversion produced a completely different food with new and different properties such as a very delicious taste.
The process of making cheese has been around for a long time and can be regarded as one of the earliest examples of biotechnology. With improved technology and science, cheese-making has become faster and in many ways more efficient.
The Process of Making Cheese
Milk contains a range of nutrients including protein and fats. It also has a lot of water. From a gallon or 8 pounds of milk, only about 1.25 of cheese can be produced. To make cheese, a combination of biological or living components and chemical compounds are required in addition to the milk. Micro-organisms such as bacteria play a very important role. Complex protein catalysts, or enzymes, and acids formed from the milk are also needed.
The first stage of the process of making a basic cheese such as cheddar involves inoculating the milk using rennet and lactic acid bacteria. Rennet is a complex mix of enzymes usually produced from the stomachs of ruminant animals. The purpose of these enzymes is to modify the proteins in milk. One of the enzymes in rennet is rennin, and this converts caseinogen, a common milk protein, into casein. Casein is insoluble in water and precipitates out of the mixture to form curds. The casein gel also contains most of the calcium and fat from the milk. The lactic acid bacteria convert the lactose sugar in milk into lactic acid. The result as this stage after the production of lactic acid and rennin is curdled milk that has separated out into curds and whey. The curds contain proteins, fats, and milk solids. The whey is primarily water.
The next stage is to allow the lactic acid bacteria to do their work and produce more lactic acid. The curds and whey must soak until the lactic acid concentration meets the requirements. From there, the watery portion known as the whey is drained off. Salt is one of the main preservatives in cheese, and this is added at this point.
With just the curds remaining, these go on to be pressed in a cheese press to remove any whey that is still present, firstly. The pressure is increased gradually until it reaches a high level, which can be around a ton of pressure. This allows the cheese to solidify.
After the cheese is solid, it is given several months to age and ripen in a cool place. This improves the consistency of the cheese as well as the taste. During the aging process, the biochemical processes do not cease. Enzymes and bacteria go on working and making changes to the fats, proteins, and sugars in the cheese. Different variations in the cheese-making process create a broad range of unique cheese varieties. After allowing the cheese to age for at least a year, you can have a sharp cheddar cheese. Swiss cheese, on the other hand, is aged for a few weeks in a cool temperature then transferred to a warmer place for another month or so. Special bacteria are also added at this stage.