Mercury Contamination in Seafood: What You Need to Know
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Cheese making is a craft that blends both art and science. It's a process that transforms the humble milk into a myriad of flavors, textures, and forms. This transformation relies on numerous factors, such as the type of milk used, the microbial flora introduced, the manufacturing process, and the maturation environment. Let's delve deeper into the fascinating world of cheese making.
The fundamental ingredient for cheese making is milk. The type of milk used can significantly influence the final product. Milk from different sources, such as cows, buffaloes, and goats, can be used either individually or in combination. The key requirement is that the milk must be rich in caseins, the proteins that coagulate to form cheese.
The process of cheese making begins with preparing the milk. Freshly obtained milk needs to be immediately refrigerated and used within two days. The milk's lipid content needs to be standardized according to the type of cheese being made. For full-fat cheeses, the lipid content should not be less than 3.3-3.4%, and for semi-fat cheeses, a lipid content of 2.5% is sufficient.
The next step involves a heat treatment, usually pasteurization. This process is mandatory for fresh cheeses, but not for matured ones, as the maturation conditions prevent the proliferation of harmful microorganisms. Pasteurization can be carried out at lower temperatures for longer durations or at higher temperatures for shorter durations, but the temperature should never exceed 75°C, as this would denature the proteins and impair their ability to coagulate.
Following pasteurization, the milk is inoculated with a standardized microbial starter, consisting of lactic acid bacteria. These bacteria play a crucial role in the cheese making process, as they acidify the milk and contribute to the cheese's flavor. For certain types of cheese, other microorganisms, such as molds, can also be added.
The next critical phase in cheese making is coagulation, which can be either acidic or rennet-based. Acidic coagulation occurs when bacteria ferment lactose to lactic acid, causing a drop in pH and leading to protein coagulation. Rennet coagulation, on the other hand, involves the use of specific enzymes that act on caseins, triggering coagulation.
Coagulation leads to the formation of a gelatinous mass known as curd. This curd contains fat globules and droplets of whey, which is a by-product of cheese making that contains sugars, mineral salts, and water-soluble components. The curd is then broken to facilitate the draining of whey and extend the preservation time of the cheese.
After the curd has been formed and drained, it undergoes various processes according to the type of cheese being made. For cooked cheeses, the curd is heated, while for raw cheeses, the curd is directly extracted. The curd is then shaped, salted, and subjected to a maturation period. The duration and conditions of maturation significantly influence the cheese's texture, flavor, and appearance.
Different types of cheese can be made by varying the milk source, the microbial starters used, the coagulation method, and the maturation process. Blue cheeses, for instance, are made by adding mold spores to the milk. Low-fat cheeses are made using partially skimmed or skimmed milk. Cheeses rich in calcium are often made using milk from sources high in this mineral.
Cheeses can be classified based on various factors, each contributing to the unique taste, texture, and nutritional profile of the cheese.
One of the most common ways to categorize cheese is by its fat content. Traditionally, cheeses have been divided into the following categories:
Cheese is primarily composed of water, proteins, and fat, usually in a 50:25:25 ratio. However, these proportions can vary depending on the type and maturation period of the cheese. Cheese is a high-energy food, providing an average of 300 kcal per 100 grams, primarily due to its lipid content.
Cheese is rich in calcium, phosphorus, vitamin A, and B vitamins. However, it lacks vitamin C and iron, so it's best to pair it with vegetables.
The cholesterol content in cheeses fluctuates between 60 - 100 milligrams (mg) per 100 grams of the edible part. While this is significant, it's not excessive, especially considering that meats contain almost similar quantities.
The cholesterol content in cheese is primarily influenced by:
Interestingly, the concentration of free water is inversely proportional to the maturation process. As the cheese matures, the free water content decreases, leading to an increase in cholesterol and saturated fats. Conversely, the lactose content decreases as the cheese matures.
In conclusion, making cheese is a blend of science and art. It involves a deep understanding of the properties of milk, the role of microbial activity, and the effects of different processes on the final product. Whether you're a cheese lover, a home cook, or a professional cheese maker, there's always more to learn and explore in the world of cheese.