Which enzyme curdles milk in human infants?

Which enzyme curdles milk in human infants?

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Following, this question -

Do humans produce rennin? Rennin does not exist. And What inactivates pepsin in infants?

Rennin exist.

What do I know is-

Rennin is found in calves and acts on milk to curdle it.

Pepsin acts as rennin at pH of 6-6.5 and curdles milk.

Humans have pepsin, in infants as well as adults. Pepsin can perform both functions in humans.

So, in infants, is curdling of milk done by rennin or the rennin like activity of pepsin?

Human, donkey and cow milk differently affects energy efficiency and inflammatory state by modulating mitochondrial function and gut microbiota

Different nutritional components are able, by modulating mitochondrial function and gut microbiota composition, to influence body composition, metabolic homeostasis and inflammatory state. In this study, we aimed to evaluate the effects produced by the supplementation of different milks on energy balance, inflammatory state, oxidative stress and antioxidant/detoxifying enzyme activities and to investigate the role of the mitochondrial efficiency and the gut microbiota in the regulation of metabolic functions in an animal model. We compared the intake of human milk, gold standard for infant nutrition, with equicaloric supplementation of donkey milk, the best substitute for newborns due to its nutritional properties, and cow milk, the primary marketed product. The results showed a hypolipidemic effect produced by donkey and human milk intake in parallel with enhanced mitochondrial activity/proton leakage. Reduced mitochondrial energy efficiency and proinflammatory signals (tumor necrosis factor α, interleukin-1 and lipopolysaccharide levels) were associated with a significant increase of antioxidants (total thiols) and detoxifying enzyme activities (glutathione-S-transferase, NADH quinone oxidoreductase) in donkey- and human milk-treated animals. The beneficial effects were attributable, at least in part, to the activation of the nuclear factor erythroid-2-related factor-2 pathway. Moreover, the metabolic benefits induced by human and donkey milk may be related to the modulation of gut microbiota. In fact, milk treatments uniquely affected the proportions of bacterial phyla and genera, and we hypothesized that the increased concentration of fecal butyrate in human and donkey milk-treated rats was related to the improved lipid and glucose metabolism and detoxifying activities.

Keywords: Microbiota Milk Mitochondria Redox-status SCFAs.

Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Investigating the effect of temperature on the action of a protease enzyme on exposed developed film

Aim: The aim of the experiment is to find out what effect temperature has on the action of a protease enzyme on exposed developed film.

Enzymes are biological catalysts. They are made in livings things built up by amino acids to make protein. Enzymes are able to speed up reactions and can repeat reactions.

There are various factors that affect the activity of enzymes they are:

"Y Concentration of enzyme or substrate

Enzymes are specific, this means that they only work on one substrate molecule. A substrate molecule is what the enzyme actually works on.

The factors I have chosen to investigate are temperature. This therefore means that the temperature will be the independent variable.

In the experiment there will be a transparent plastic backing of developed film, which will have a black gelatine coat on it. The gelatine coat is protein, which is the substrate molecule. I will put the film into protease solution, which is the enzyme. By having the gelatine coat I am able to see what happens to the gelatine coat when the temperature increases. I can find out if temperature affects the action of a protease enzyme.

Enzymes have an optimum temperature, which is generally below 400C. The optimum temperature is when enzymes works best and fastest at. When the temperature rises the rate increases. This is because the substrate and enzyme molecules are moving faster because the temperature has increased. This means that the molecules have more energy. They therefore are likely to collide more often with each other and a reaction will take place. However if the temperature goes over the optimum temperature the reaction slows down and the enzyme denatures. This means that it has changed shape and therefore the substrate can no longer fit into the enzyme.

The diagram below shows how the substrate molecules which is protein fits into the enzyme, which is a protease molecule. This type of mechanism is called the lock and key hypothesis.

If the active site, which is the enzyme, is heated too much it will change shape and no longer fit the substrate. The substrate therefore no longer is able to react if there is no active enzyme.

I predict that when the temperature increases the time taken for the gelatine to be broken down will decrease. This is because temperature is a catalyst, which helps to speed up the enzymes, which are biological catalysts. When the temperature is 300C I predict that it will take longer for the film to become transparent than when the film is in a temperature of 600C. However at a certain temperature in the experiment I predict that there will be an optimum temperature. This is when the enzyme works best at. After this point the enzymes start to slow down and eventually denature which means it is harder for the substrate molecules to fit into the enzyme molecules.

As I predict that when the temperature increases the time taken for the gelatine to be broken down decreases until it reaches the optimum temperature I therefore predict that the rate of reaction will increase when the temperature increases until it reaches the point when the enzymes start to denature.

When the temperature is increased the enzyme molecules will break down the black gelatine coat quicker and therefore the developed film will become transparent faster. When temperature is increased the substrate molecules of protein will collide more frequently with the enzyme molecules. So if the temperature is increased from 300C to 600C the enzyme molecule will break the black gelatine down faster to leave the transparent plastic backing.

The two diagrams show the effect of temperature between substrate molecules and enzyme molecules. They are only rough diagrams of what will happen between the two molecules.

Function of Rennin Enzyme

Rennin is an enzyme that is essential for the digestion of proteins. It helps digest milk in young mammals. This BiologyWise article lists out the function of rennin enzyme.

Rennin is an enzyme that is essential for the digestion of proteins. It helps digest milk in young mammals. This BiologyWise article lists out the function of rennin enzyme.

Enzymes are organic catalysts that are produced in the body of all living organisms. The human body produces several enzymes that carry out or accelerate a number of chemical reactions in the body. Enzymes help maintain biochemical energy, and are necessary for regulating many vital body processes such as metabolism, respiration, digestion, blood clotting, coagulation, reproduction, and the process of growth and development. Rennin, which is also called chymosin or rennet, belongs to the aspartic proteinases family of enzymes. It is produced in the stomach of young mammals. This enzyme is essential for the digestion of mother’s milk in young mammals.

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Function of Rennin

Rennin is a coagulating enzyme produced in the inner lining of the abomasum (the fourth/true stomach) of the milk-fed calf. It is also produced in the stomach of a goat or a lamb. Some alternative sources of chymosin are plants, especially thistles and nettles, and microbes like fungi and yeasts. Being a proteolytic enzyme, the major function of rennin is to curdle milk. Rennin is produced in large amounts, immediately after the birth. Its production gradually decreases, and it is replaced by a digestive enzyme called pepsin.

Rennet is known to play an important role in coagulation and curdling of milk. Curdling of milk is essential for the proper digestion of milk proteins in the stomach. If milk is removed immediately from the stomach in its undigested state, then young mammals would not benefit from the milk proteins. Coagulation of milk by rennet allows it to remain for a longer time in the stomach.

So, how does rennin cause curdling of milk? Rennin is produced in the form of inactive prorennin. After consumption of milk, the hydrochloric acid in the gastric juice present in the stomach activates prorennin, and converts it into its active form, rennin. A caseinogen enzyme is present in the milk, which has four types of molecules. Rennin precipitates three of them, namely alpha-s1, alpha-s2 casein, and beta casein, in the presence of calcium in the milk. Kappa casein, which is the fourth molecule in the caseinogen enzyme, is not precipitated by calcium. Kappa casein is known to prevent the precipitation of alpha and beta caseins. Since coagulation is necessary, rennin enzyme inactivates kappa casein. In this way, milk is coagulated and properly digested.

The optimum temperature required for the reaction of milk and rennin is 37°C. At higher temperatures, the rennin enzyme molecules break down, and the action of rennin on milk ceases. If the temperature falls, it slows down the rate of reaction.

Due to its coagulating action on milk, rennin enzyme is commonly used in the food industry. It is widely used for the production of cheese. Rennin that is required for the production of cheese was earlier obtained mainly from the calf’s stomach and other non-animal sources. However, for the industrial cheese production, a large amount of rennin is required. These days, genetic engineering methods are used for obtaining large amounts of rennin enzyme that is needed in the food industry.

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Why Milk Curdles

Curdled milk is what you get when lumps form in smooth milk. Although the clumps form in spoiled milk, the chemical reaction that causes curdling also occurs in fresh milk, under the right conditions. Intentional curdling of milk is used to produce foods, such as yogurt, cheese, and buttermilk. Here’s a closer look at how curdling happens:

Curdling Chemical Reaction

Fresh milk is an example of a colloid, consisting of fat and protein particles floating in a water-based solution. The colloidal suspension scatters light, causing milk to appear white. The protein molecules, mainly casein, repel each other so they naturally distribute evenly through the liquid. Milk is slightly acidic. When the pH is lowered even more by the addition of another acidic ingredient, the protein molecules stop repelling each other. This allows them to stick together or coagulate into the clumps known as curds. The watery liquid that remains is called whey.

How Sour Milk Curdles

When milk goes “off” or turns sour, it is because acids produced by bacteria lower the pH of milk so the proteins can clump together. The increased acidity of the milk also causes it to taste sour. The bacteria living in milk naturally produce lactic acid as they digest lactose so they can grow and reproduce. This occurs whether milk is fresh or pasteurized. You won’t notice the effect on flavor until enough acid has been produced. Refrigerating milk slows the growth of bacteria. Similarly, warm milk helps bacteria thrive and also increases the rate of the clumping reaction.

Curdling Milk in Coffee and Tea

If you enjoy milk in your coffee or tea, you may have noticed sometimes milk immediately curdles when added to the hot beverage. Except for the chunkiness, the drink may taste perfectly fine. This is because coffee and tea contain just enough acidity to tip the pH of milk to the point of curdling. The effect is most often seen in milk that is close to going sour or when adding milk to very hot coffee or tea, since the high temperature can coagulate casein.

Intentional Curdling of Milk

No one wants to drink chunky milk straight from the fridge, but the chemical reaction that causes curdling isn’t always bad. The same reaction produces buttermilk, cheese, and yogurt.

Adding lemon juice or vinegar to fresh milk is an easy way to make homemade buttermilk. Why isn’t buttermilk clumpy? It would be, if you added the acidic ingredient to hot milk. However, adding acid to cold milk allows casein to coagulate more slowly. Rather than forming clumps, the chemical reaction simply thickens the liquid. The ingredient also affects the flavor of the buttermilk, adding a tangy note.

Yogurt and cheese are slightly more complicated because you usually control the type of bacteria (the bacterial culture) used to make a product with a pleasing flavor and texture. However, fresh cheeses, such as ricotta, is very simply made by heating milk, adding an acidic ingredient, and straining the curd.

A Milk-Curdling Activity

Have you ever poured yourself a cup of milk and instead of a smooth liquid, all you get is clumps? This is usually a sign that the milk has gone bad. And if it smells sour, it probably has. But the physical process of what happened to the milk is called coagulation, which is the mechanism that occurs when proteins in the milk clump. Although you do not necessarily want this in your milk, without coagulation (or curdling) there would be no cheese or yogurt, which is why it is a very important process in the food industry. Wonder how you can make milk curdle&mdashwithout having it be spoiled? Try this activity to find out!

Humans have turned milk into a multipurpose liquid. By itself, milk is a nutrient-rich beverage. But when you start treating milk in various processes, all kinds of other products can be created such as butter, yogurt, buttermilk and cheese. Milk mostly consists of fat, protein, lactose (a kind of sugar) and water. The milk fat is suspended in the water as fine droplets, which makes it an emulsion. Milk also contains a lot of proteins that, in this case, are mostly whey and casein. Because casein is poorly soluble in water, its proteins build spherical structures called micelles that allow them to stay in suspension as if they were soluble.

With both fat and proteins in suspension, the milk is a white liquid as we know it. The micelle structures, however, can easily be disrupted or changed, and once altered they cannot be reformed. Because the micelle holds the casein protein in suspension, without it the micelles will clump together and the casein comes out of the solution. The result of this process of milk coagulation, or curdling, is a gelatinous material called curd.

The processes for making many other dairy products such as cottage cheese, ricotta, paneer and cream cheese start with milk curdling. This is why cheese producers want the milk to curdle. There are different ways to start milk coagulation. You can do it with acid or heat as well as by letting the milk age long enough or with specific enzymes (which are proteins that perform a specific chemical reaction). Chymosin, for example, is an enzyme that alters the casein micelle structure to make milk curdle. Proteases are other enzymes that disrupt the casein micelle structure by chopping up proteins, causing milk to curdle. In this activity you will try two different methods of making milk curdle&mdashand produce some cheesy results!

  • Milk
  • Lemon (fresh)
  • Pineapple (fresh)
  • Lemon squeezer
  • Food grater, juicer or blender
  • Teaspoon
  • Tablespoon
  • Knife
  • Cutting board
  • Two pieces of cheesecloth or cotton fabric
  • 10 small transparent and microwavable cups (that each hold about two ounces)
  • Paper towels
  • Microwave
  • Permanent marker
  • Adult helper
  • Workspace that can tolerate spills
  • Timer (optional)


  • Mark four of the small cups with the labels &ldquopineapple juice,&rdquo &ldquopineapple juice (heated),&rdquo &ldquolemon juice,&rdquo and &ldquolemon juice (heated).&rdquo
  • Take a fresh pineapple and with the help of an adult cut off the rind on a cutting board. Only use about one fifth of the pineapple. Cut the flesh in smaller pieces and grate it. Alternatively, you can use a juicer or blender. Then, place the grated fruit in a piece of cheesecloth and squeeze at least one teaspoon of juice into each cup that you labeled with &ldquopineapple juice.&rdquo
  • Put the cup that you labeled &ldquopineapple juice (heated)&rdquo into the microwave and heat it just long enough to get it boiling (about 10 to 20 seconds). When it starts to boil, carefully take it out of the microwave and let it cool down.
  • Take a fresh lemon and use the lemon squeezer to make lemon juice. Add at least one teaspoon of juice into each cup that you labeled with &ldquolemon juice.&rdquo
  • Again, put the cup labeled &ldquolemon juice (heated)&rdquo into the microwave and heat it for 10 to 20 seconds. Once it starts boiling, carefully take it out and let it cool down.
  • Label four of the remaining cups &ldquo1&rdquo to &ldquo4.&rdquoFill each of these cups with about one tablespoon of milk.
  • Label the last two cups &ldquocurd&rdquo and &ldquowhey.&rdquo
  • Place the cup that you labeled &ldquo1&rdquo in front of you. It should contain one tablespoon of milk. How does the milk look? What happens if you gently swirl the milk in the cup? Do you notice anything unusual?
  • Use a clean teaspoon to add one teaspoon of the freshly squeezed lemon juice to your milk in cup 1. Swirl the cup slightly. Does the milk change when you add the lemon juice? If yes, does the change occur immediately or after awhile? When you swirl the cup a little bit, what do you observe at the wall of the cup?
  • Take your second cup of milk and this time add one teaspoon of the heated lemon juice. Do you see the same reaction happening as before? How does the milk change? Is the reaction as fast as the previous one?
  • Use your third cup of milk, and with a clean teaspoon add one teaspoon of pineapple juice to the milk. Observe what is happening for about five minutes. Does the milk curdle with pineapple juice? Is the reaction fast or slow compared with that of the lemon juice?
  • To the fourth cup of milk add a teaspoon of heated pineapple juice and swirl the cup slightly. Again, observe the cup for about five minutes. Do you get a similar result again or is it different? If yes, how is it different? What do you think happened? Can you explain your observations?
  • Choose the cup with milk that gave you the greatest amount of curd. Then, place your second cheesecloth over the cup labeled &ldquowhey&rdquo and carefully pour the curdled milk mixture onto the cloth. Fold the cloth over the curdled milk and squeeze the liquid from the mixture into the cup. Do you see a lot of liquid coming out of the cheesecloth? What does the liquid look like? Is it clear, does it have a color or does it still look like milk? What do you think the liquid is?
  • Once you have squeezed out all the liquid, open the cheesecloth and scoop the curd into the cup labeled &ldquocurd.&rdquo How much curd did you get, and what does it look like? Does it remind you of a cheese product? How does it feel if you touch it with your fingers? What parts of the milk do you think are inside the curd?
  • If you want (and only if you used clean materials!), you can taste a little bit of the whey and curd. Does it taste similar to milk? Is it sweet, sour, creamy or salty? Does it remind you of a particular food?
  • Extra:What other solutions can make milk curdle? Try out different fruit juices or other edible liquids that you find in your kitchen and test how your milk reacts to these. Remember that acidity (how sour something is) and enzymes are good ways to make milk curdle!
  • Extra: How much pineapple or lemon juice is necessary to make milk curdle? To find out you could repeat this activity, but this time change the amount of juice that you add to your milk. Is one drop enough or do you need 10? How many drops does it take to make the milk start to curdle?
  • Extra: In this activity you tested one kind of milk. Do you think other milks such as fat-free and lactose-free milk or coconut and almond milk will give you the same or similar results? There is only one way to find out: test it!
  • Extra:Do you want more cheesy results? Then use this activity to make some real cottage cheese. An example recipe is given below in the "More to explore" section.

Observations and results
Did you see some nice clump formation in your milk? Whereas regular milk looks smooth and white, it changes very fast when you add a teaspoon of lemon juice. It almost immediately gets thicker in consistency, and you see white clumps forming that stick to the cup wall when you swirl the milk slightly. The clumps, or curd, consist of casein proteins that are usually in solution where they form micelle structures. These structures are very fragile, and when you change the conditions of the solution, they can easily break up and form clumps of casein proteins. This can happen if you change the pH, or acidity, of the milk, which means making it sourer. Lemon juice is very acidic, and that is why you see the casein proteins clumping once you add it. Heating the lemon juice does not affect its acidity, which means when you added heated lemon juice to your milk, the exact same reaction should have occurred.

Pineapple juice, on the other hand, is not acidic enough to break the micelle structure of the casein proteins. Your milk still clumps when you add it, however. This time, it is not the acidity but special enzymes within the pineapple that make the milk curdle. The pineapple contains an enzyme extract called bromelain, which contains a protease enzyme that chops up the casein proteins, destroying their micelle structure. You might have noticed the curdling did not happen as quickly with pineapple juice as with lemon juice&mdashthe enzymes need some time to activate&mdashbut within five minutes the milk should have looked very clumpy. Many enzymes are deactivated when heated. When you put the pineapple juice in the microwave, the enzymes will not work anymore. This is why no milk curdling occurs when you added the heated pineapple juice.

Filtering out the curd through a cheesecloth results in a whitish-yellow solution called whey, which consists of about 94 percent water and four to five percent lactose and whey proteins. The solid part, the curd, looks like cottage cheese&mdashand it actually is! If you want to make it really tasty, look at the recipe below given in the "More to explore" section.

Pour all your solutions including the curdled milk into the sink. You can discard/recycle your cups or wash them with soapy water if you want to reuse them. Wipe down your work area with a wet paper towel.

More to explore
Milk Chemistry, from the Cheese Science Toolkit
Sculpted Science: Turn Milk into Plastic!, from Scientific American
Cottage Cheese Recipe, from The Weekend Artisan
Making Milk Curdle with Pineapple Enzymes, from Science Buddies
Science Activities for All Ages!, from Science Buddies

This activity brought to you in partnership with Science Buddies

Lipases in human milk: effect of gestational age and length of lactation on enzyme activity

Human milk contains two lipases, bile salt-stimulated lipase (BSSL) and lipoprotein lipase (LPL). In the mammary gland, LPL provides long-chain fatty acid for milk fat synthesis. LPL has no known function in milk, but has been implicated in milk fat hydrolysis during cold storage. BSSL may have an important role in infant fat digestion. The aims of the present studies were to assess (1) the methodological validity of using whole milk to analyze BSSL activity, (2) the longitudinal variation of BSSL and LPL activity in the milk of mothers delivering premature and full-term infants, and (3) the stability of BSSL and LPL activity during cold storage. Diluted whole milk and purified BSSL were shown to have similar characteristics. LPL activity was equally stable at -20 and -70 degrees C, whereas BSSL activity was higher in milks stored at -70 than at -20 degrees C (38.8 +/- 0.88 vs 33.3 +/- 0.87 U/ml milk, respectively 1U = 1 mumol free fatty acid release/min). Levels of BSSL activity in preterm and term milk were similar. LPL activity tended to be higher in term milk. Overall, BSSL activity showed significant longitudinal variation, being highest at 1 and 3 weeks of lactation (43.2 +/- 0.04 and 42.6 +/- 1.03 U/ml milk, respectively). For LPL, the longitudinal pattern of activity depended upon the length of pregnancy. Implications for infant nutrition and mammary gland biology are discussed.

A physiological role of breast milk leptin in body weight control in developing infants

Objective: Leptin, a hormone that regulates food intake and energy metabolism, is present in breast milk. The aim of this study was to determine whether milk leptin concentration is correlated with maternal circulating leptin and BMI and with body weight gain of infants.

Research methods and procedures: A group of 28 non-obese women (BMI between 16.3 and 27.3 kg/m(2)) who breast-fed their infants for at least 6 months and their infants were studied. Venous blood and milk samples were obtained from mothers at 1, 3, 6, and 9 months of lactation, and leptin concentration was determined. Infant body weight and height were followed until 2 years of age.

Results: During the whole lactation period, milk leptin concentration correlated positively with maternal plasma leptin concentration and with maternal BMI. In addition, milk leptin concentration at 1 month of lactation was negatively correlated with infant BMI at 18 and 24 months of age. A better negative correlation was also found between log milk leptin concentration at 1 and at 3 months of lactation and infant BMI from 12 to 24 months of age.

Discussion: We concluded that, in a group of non-obese mothers, infant body weight during the first 2 years may be influenced by milk leptin concentration during the first stages of lactation. Thus, moderate milk-borne maternal leptin appears to provide moderate protection to infants from an excess of weight gain. These results seem to point out that milk leptin is an important factor that could explain, at least partially, the major risk of obesity of formula-fed infants with respect to breast-fed infants.

The digestive process starts in the mouth, where your slightly acidic saliva combines with milk and starts to break it down. When you swallow the milk, it travels down the esophagus and into the stomach. Gastric juices in the stomach break down the milk further and kill any living bacteria. The stomach then sends the milk into the small intestine, where nutrients -- such as amino acids, the building blocks of protein, and fatty acids, the building blocks of fat -- are absorbed. Materials that are not absorbed for energy or nutrition are pushed on to the large intestine, processed as fecal matter and released through the rectum. Waste fluids -- water carrying unwanted materials -- fill the bladder and are released as urine.

Lactase is a key enzyme in the digestion of lactose. The small intestine produces lactase. If your body only produces a small amount of lactase, you have what is called a lactose sensitivity. You can have lactose in small amounts of milk and other dairy products, but you experience pain and discomfort if you consume too much. If the small intestine doesn't process lactose, it moves on to the large intestine, where bacteria ferment the sugar, producing carbon dioxide. The result is gas, bloating, cramping and diarrhea.


The chymosin is found in a wide range of tetrapods, [2] although it is best known to be produced by ruminant animals in the lining of the abomasum. Chymosin is produced by gastric chief cells in newborn mammals [3] to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. Non-ruminant species that produce chymosin include pigs, cats, seals, [4] and chicks. [2]

One study reported finding a chymosin-like enzyme in some human infants, [5] but others have failed to replicate this finding. [6] Humans have a pseudogene for chymosin that does not generate a protein, found on chromosome 1. [4] [7] Humans have other proteins to digest milk, such as pepsin and lipase. [8] : 262

In addition to the primate lineage leading up to humans, some other mammals have also lost the chymosin gene. [2]

Chymosin is used to bring about the extensive precipitation and curd formation in cheese-making. The native substrate of chymosin is K-casein which is specifically cleaved at the peptide bond between amino acid residues 105 and 106, phenylalanine and methionine. [9] The resultant product is calcium phosphocaseinate. [ citation needed ] When the specific linkage between the hydrophobic (para-casein) and hydrophilic (acidic glycopeptide) groups of casein is broken, the hydrophobic groups unite and form a 3D network that traps the aqueous phase of the milk.

Charge interactions between histidines on the kappa-casein and glutamates and aspartates of chymosin initiate enzyme binding to the substrate. [9] When chymosin is not binding substrate, a beta-hairpin, sometimes referred to as "the flap," can hydrogen bond with the active site, therefore covering it and not allowing further binding of substrate. [1]

Listed below are the ruminant Cym gene and corresponding human pseudogene:

Because of the imperfections and scarcity of microbial and animal rennets, producers sought replacements. With the development of genetic engineering, it became possible to extract rennet-producing genes from animal stomach and insert them into certain bacteria, fungi or yeasts to make them produce chymosin during fermentation. [11] [12] The genetically modified microorganism is killed after fermentation and chymosin is isolated from the fermentation broth, so that the fermentation-produced chymosin (FPC) used by cheese producers does not contain any GM component or ingredient. [13] FPC contains the identical chymosin as the animal source, but produced in a more efficient way. FPC products have been on the market since 1990 and are considered the ideal milk-clotting enzyme. [14]

FPC was the first artificially produced enzyme to be registered and allowed by the US Food and Drug Administration. In 1999, about 60% of US hard cheese was made with FPC [15] and it has up to 80% of the global market share for rennet. [16]

By 2008, approximately 80% to 90% of commercially made cheeses in the US and Britain were made using FPC. [13] The most widely used fermentation-produced chymosin is produced either using the fungus Aspergillus niger or using Kluyveromyces lactis.

FPC contains only chymosin B, [17] achieving a higher degree of purity compared with animal rennet. FPC can deliver several benefits to the cheese producer compared with animal or microbial rennet, such as higher production yield, better curd texture and reduced bitterness. [14]

Watch the video: Biology Lab - Enzymes effect of pepsin on milk (November 2022).