Rennet in the context of "Rennin"

Cheese is a type of dairy product produced in a range of flavors, textures, and forms by coagulation of the milk protein casein. It is composed of proteins and fat from milk, usually of cows, goats or sheep, and sometimes of water buffalo. During production, milk is usually acidified and either the enzymes of rennet or bacterial enzymes with similar activity are added to cause the casein to coagulate. The solid curds are then separated from the liquid whey and pressed into finished cheese. Some cheeses have aromatic molds on the rind, the outer layer, or throughout.

Over a thousand types of cheese exist, produced in various countries. Their styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether they have been pasteurised, the butterfat content, the bacteria and mold, the processing, and how long they have been aged. Herbs, spices, or wood smoke may be used as flavoring agents. Other added ingredients may include black pepper, garlic, chives or cranberries. A cheesemonger, or specialist seller of cheeses, may have expertise with selecting, purchasing, receiving, storing and ripening cheeses.

An animal product is any material derived from the body of a non-human animal or their excretions. Examples are meat, fat, blood, milk, eggs, honey, and lesser known products, such as isinglass, rennet, and cochineal.

The word animals includes all species in the biological kingdom Animalia, except humans. This includes, for example, tetrapods, arthropods, and mollusks. Generally, products made from decomposed animals, such as petroleum, or crops grown in soil fertilized with animal remains or manure are not characterized as animal products. Products sourced from humans (e.g. breast milk) are not typically classified as animal products.

A lacto-vegetarian (sometimes referred to as a lactarian; from the Latin root lact-, meaning milk) diet abstains from the consumption of eggs as well as meat, while still consuming dairy products such as milk, cheese (without animal rennet, i.e., from microbial sources), yogurt, butter, ghee, cream, and kefir, as well as honey.

Curd is obtained by coagulating milk in a sequential process called curdling. It can be a final dairy product or the first stage in cheesemaking. The coagulation can be caused by adding rennet, a culture, or any edible acidic substance such as lemon juice or vinegar, and then allowing it to coagulate. The increased acidity causes the milk proteins (casein) to tangle into solid masses, or curds. Milk that has been left to sour (raw milk alone or pasteurized milk with added lactic acid bacteria) will also naturally produce curds, and sour milk cheeses are produced this way.

Producing cheese curds is one of the first steps in cheesemaking; the curds are pressed and drained to varying amounts for different styles of cheese and different secondary agents (molds for blue cheeses, etc.) are introduced before the desired aging finishes the cheese. The remaining liquid, which contains only whey proteins, is the whey. In cow's milk, 90 percent of the proteins are caseins. Curds can be used in baking or may be consumed as a snack.

Whey, also known as milk serum, is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct of the making of rennet types of hard cheese, like cheddar or Swiss cheese. Acid whey (also known as sour whey) is a byproduct of the making of acidic dairy products such as strained yogurt.

Whey proteins consist of β-lactoglobulin (48%–58%), α-lactalbumin (13%–19%), Glycomacropeptide (12%–20%), bovine serum albumin, heavy and light chain immunoglobulins and several minor whey proteins.

Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking.

In general, fermentations can be divided into four types:

Mare milk is milk lactated by female horses, known as mares, to feed their foals. It is rich in whey protein, polyunsaturated fatty acids and vitamin C, and is a key ingredient in kumis. In several European countries, including Germany, it is sold powdered.

Mare milk is sometimes chosen over cow milk for its purported health benefits. A niche market considers it a remedy for skin or digestive problems. Peer-reviewed papers suggest it can reduce atopic dermatitis or eczema. It is used to make cosmetics and can form cheese with camel rennet, but not bovine.

Quark or quarg (sometimes translated as curd cheese) is a type of fresh dairy product made from milk. The milk is soured, usually by adding lactic acid bacteria cultures, and strained once the desired curdling is achieved. It can be classified as fresh acid-set cheese. Traditional quark can be made without rennet, but in modern dairies small quantities of rennet are typically added. It is soft, white and unaged, and usually has no salt added.

Quark and its dryer variant tvorog are traditional in the cuisines of Baltic, Germanic and Slavic-speaking countries as well as amongst French, Romanians, Italians, Hungarians, Greeks, Ashkenazi Jews and various Turkic peoples. Quark is similar to other fresh cheeses including the French fromage blanc, cottage cheese, and farmer cheese.