Patrick Oconnell
Rennet, a complex set of enzymes produced in the stomachs of ruminant mammals, is used to make cheese. It contains chymosin, a protease enzyme that curdles casein in milk, separating it into solid curds and liquid whey. While traditional rennet came from calf stomachs, cheese makers have explored alternative sources, including microbial, vegetable, and plant enzymes, to address limited availability and cater to vegetarian and vegan diets. Today, most cheese is made with chymosin derived from bacterial sources, with animal rennet accounting for less than 5% of cheese production in the United States.
| Characteristics | Values |
|---|---|
| Name of enzyme used to make cheese | Rennet |
| What is it? | A complex set of enzymes produced in the stomachs of ruminant mammals |
| Key component | Chymosin, a protease enzyme that curdles the casein in milk |
| Other enzymes in rennet | Pepsin, lipase |
| Rennet from calves | Less common today, with less than 5% of cheese in the US made using it |
| Modern sources of chymosin | Bacterial, microbial, vegetable |
| Other sources of enzymes for cheese-making | Plants, fungi, microbial sources |
| Examples of plants used | Fig juice, several species of Galium, dried caper leaves, nettles, thistles, mallow, Withania coagulans, ground ivy |
| Vegetable rennet | Used in kosher and halal cheese production, contains extract from the mold Rhizomucor miehei |
| Microbial rennet | Used in vegan cheese production, provided no animal-based ingredients are used |
| Other enzymes used in dairy | Protease, lipase |
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What You'll Learn
Rennet, a complex set of enzymes, is used to make cheese
The use of rennet in cheese-making has a long history, dating back to Roman times. However, due to the limited availability of mammalian stomachs, cheese makers have explored alternative sources of enzymes, including plants, fungi, and microbial sources. Today, most cheese is made using chymosin derived from bacterial sources, with less than 5% of cheese in the United States made using animal rennet.
The type of rennet used can vary depending on the cheese being produced. For example, traditional calf rennet, which contains chymosin and pepsin in a natural ratio, is suitable for certain cheese styles and results in a desirable flavour profile. On the other hand, vegetable rennet, derived from plants or fungi, may be used in the production of kosher and halal cheeses, but it can lead to bitter flavours in cow's milk cheeses.
The development of substitutes for animal rennet has been driven by increasing cheese production and meat demand, which could lead to a shortage of calves and, consequently, rennet. These substitutes include extracts from adult cows and pigs, as well as microorganisms that have been genetically modified to yield GM rennet, the most cost-effective option currently.
The use of rennet in cheese-making raises considerations for those following a vegetarian diet. While some sources suggest that cheese can still be considered vegetarian if one's form of vegetarianism includes dairy, others opt for cheeses without calf rennet. It is worth noting that the slaughter of calves is primarily for veal production, and rennet is considered a "by-product" of that slaughter.
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Rennet comes from the stomachs of ruminant mammals
Rennet is a set of enzymes produced in the stomachs of ruminant mammals. It is used in the production of cheese to separate milk into solid curds and liquid whey. The key component of rennet is chymosin, a protease enzyme that curdles casein, the main protein in milk. Rennet also contains other enzymes such as pepsin and lipase.
The use of rennet in cheese-making dates back to Roman times, with the traditional source of rennet being the stomachs of young mammals, particularly calves. However, due to the limited availability of mammalian stomachs, cheese makers have explored alternative sources of enzymes, including plants, fungi, and microbial sources.
Today, most cheese is made using chymosin derived from bacterial sources, with less than 5% of cheese in the United States produced using animal rennet. This shift has been driven by the development of substitutes, such as extracts from adult cows and pigs, and the use of genetically modified microorganisms to produce GM rennet, which is more cost-effective.
The type of rennet used can vary depending on the specific cheese being produced. For example, some traditional cheese productions in the Mediterranean use enzymes from thistle or Cynara (artichokes and cardoons), while kid goat rennet is used for goat's milk and lamb rennet for sheep's milk.
The process of extracting rennet from animal sources involves drying and cleaning the stomachs of young calves before slicing them into small pieces and soaking them in salt water or whey with vinegar or wine to lower the pH. This process results in a crude rennet solution that can coagulate milk, a crucial step in cheese-making.
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Chymosin, a key component of rennet, curdles milk
Rennet is a complex set of enzymes produced in the stomachs of ruminant mammals. It has been traditionally used to separate milk into solid curds and liquid whey, which are used to make cheese. Chymosin, a key component of rennet, is a protease enzyme that curdles the casein in milk. Casein is the main protein in milk.
Chymosin is responsible for coagulating milk, while another enzyme in rennet, pepsin, impacts the aging process of cheese. Calf rennet contains these two enzymes in a natural ratio that is suitable for cheesemaking. However, the limited availability of calf rennet and ethical concerns have led to the development of alternative sources of chymosin.
Chymosin can be obtained from microbial or vegetable sources, although these sources may not be sufficient for producing certain types of cheese, such as cheddar and hard cheeses. To address this issue, scientists have genetically engineered microorganisms to produce recombinant chymosin during fermentation, resulting in fermentation-produced chymosin (FPC). This bioengineered enzyme is now associated with the creation of a significant proportion of cheeses, reducing the need for calf rennet and offering a more cost-effective solution.
The use of FPC has sparked debates around genetic modification, with some countries banning its use in food products. Nonetheless, FPC is considered safe and reliable by many cheese producers, contributing to a healthy food system. Over 80% of cheese consumed in North America is made from non-animal sources of chymosin, ensuring suitability for vegetarians and those with dietary restrictions.
In summary, chymosin, a key component of rennet, plays a crucial role in curdling milk by coagulating casein. The development of alternative sources of chymosin, such as FPC, has revolutionized the cheese industry, addressing supply constraints, ethical concerns, and dietary preferences while also enhancing the sustainability and cost-effectiveness of cheese production.
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$6.5
Calf rennet is a traditional coagulant for cheese
Rennet is a set of enzymes produced in the stomachs of ruminant mammals. It has traditionally been used to separate milk into solid curds and liquid whey, which are used in cheesemaking. Chymosin, the key component of rennet, is a protease enzyme that curdles the casein in milk.
The use of rennet in cheesemaking dates back thousands of years. One origin tale speaks of a nomadic shepherd who travelled with milk in a sack made from the stomach of a young animal. Upon arrival at his destination, the shepherd found that the milk had curdled into a solid. This story illustrates the role of rennet in the science of cheesemaking.
Over time, the demand for cheese production has increased, while the supply of calf rennet has decreased. This has led to the development of alternative sources of rennet, such as microbial rennets and genetically modified microorganisms that can produce rennet enzymes. However, traditional calf rennet is still valued for its reliable results in yield and flavour profile, contributing to less defective cheese.
In summary, calf rennet is a traditional coagulant for cheese, playing a crucial role in transforming milk into solid curds. Its natural ratio of chymosin and pepsin makes it a suitable choice for cheesemakers seeking specific sensory characteristics in their products.
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Fermentation-produced chymosin is widely used in industrial cheesemaking
Chymosin is a protease enzyme that curdles the casein in milk. It is the key component of rennet, a complex set of enzymes produced in the stomachs of ruminant mammals. Rennet has traditionally been used to separate milk into solid curds and liquid whey, which are used in cheesemaking.
However, due to the limited availability of mammalian stomachs for rennet production, cheese makers have sought alternative methods of milk coagulation since Roman times. Various plants, such as thistle, cardoon, and fig juice, have coagulating properties and can be used as substitutes for animal rennet.
To overcome the limitations of animal rennet and plant-based substitutes, fermentation-produced chymosin (FPC) has been developed and is now widely used in industrial cheesemaking. FPC is produced by introducing rennet genes into certain bacteria, fungi, or yeasts, which then produce recombinant chymosin during fermentation. This process saves the lives of calves and provides an ethical alternative for those allergic to foods made with genetically modified organisms (GMOs).
FPC is less expensive than animal rennet, making it a cost-effective option for industrial cheesemaking. As of 2008, 80-90% of cheeses in the United States and Britain utilized FPC. However, it is important to note that FPC is considered a GMO and has been banned in several countries that do not allow the genetic engineering of food products.
In summary, fermentation-produced chymosin is a widely adopted alternative to traditional animal rennet in industrial cheesemaking due to its cost-effectiveness, ethical considerations, and availability. However, the ongoing debate around its status as a GMO and associated regulations in different countries remains a factor to consider for cheese producers and consumers alike.
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Frequently asked questions
Rennet is a complex set of enzymes produced in the stomachs of ruminant mammals. It is used to separate milk into solid curds and liquid whey, which is used in the production of cheeses.
There are several types of rennet, including calf rennet, microbial rennet, vegetable rennet, and fruit tree rennet. Calf rennet contains two enzymes, chymosin and pepsin, which help with coagulation and the aging process.
Natural enzymes used to make cheese include chymosin, pepsin, and lipase. Chymosin is the key component of rennet and can be derived from animals, microbial sources, or vegetables. Pepsin is found in calf rennet, while lipase is from animal or microbial sources.
