Whey 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 resulting from the manufacture of rennet types of hard cheese, like cheddar or Swiss cheese. Acid whey (also known as sour whey) is a byproduct brought out during the making of acid types of 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. [1]
Sweet whey and acid whey are similar in gross nutritional analysis. By mass both contain 93% water, about 0.8% protein, and about 5.1% carbohydrates. Sweet whey contains about 0.4% fat while sour whey contains about 0.1% fat. [2] The carbohydrates are mainly lactose. The proteins are known as lactalbumin. Whey also contains some minerals. [3]
To produce cheese, rennet or an edible acid is added to heated milk. This makes the milk coagulate or curdle, separating the milk solids (curds) from the liquid whey. [4] Sweet whey is the byproduct of rennet-coagulated cheese, and acid whey (also called sour whey) is the byproduct of acid-coagulated cheese. [5] Sweet whey has a pH greater than or equal to 5.6; acid whey has a pH less than or equal to 5.1. [6]
The fat from whey is removed and then processed for human foods (see whey butter). [3] Processing can be done by simple drying, or the relative protein content can be increased by removing lipids and other non-protein materials. [7] For example, spray drying after membrane filtration separates the proteins from whey. [8]
Heat denatures whey proteins, causing them to coagulate into a protein gel that may be useful in some foods. Sustained high temperatures above 72 °C can denature whey proteins. [7] Heat-denatured whey can still cause allergies in some people. [9]
Whey is used to produce whey cheeses such as ricotta, Norwegian brunost, and whey butter and many other products for human consumption. The fat content of whey is low; for example 1,000 pounds of whey are required to make a few pounds of whey butter. [10] It is also an additive in many processed foods, including breads, crackers, and commercial pastry, and in animal feed. Whey proteins consist primarily of α-lactalbumin and β-lactoglobulin. Sweet whey contains glycomacropeptide (GMP). It is also an abundant source of lactose which can further be used for the synthesis of lactose-based bioactive molecules. [11]
Dairy whey remaining from home-made cheesemaking has many uses. It is a dough conditioner [12] and can be substituted for skimmed milk in most baked good recipes that require milk (bread, pancakes, muffins, etc.). [13] [14]
Throughout history, whey was a popular drink in inns and coffee houses. When Joseph Priestley was at college at Daventry Academy, 1752–1755, he records that, on the morning of Wednesday, 22 May 1754, he "went with a large company to drink whey." [15] This was probably "sack whey" or "wine whey".[ clarification needed ]
Whey is also one of the main ingredients of Rivella, a carbonated drink in Switzerland.
Another use of whey is to make "cream of tartar whey": "Put a pint of blue milk [skim milk] over the fire, when it begins to boil, put in two tea spoonfuls of cream of tartar, then take it off the fire, and let it stand till the curd settles to the bottom of the pan, then put it into a basin to cool, and drink it milk warm." This is known as heat-acid coagulation. [16]
In areas where cheese is made, excess whey byproduct is sometimes sprayed over hay fields as a fertilizer. [17]
Historically whey, being a byproduct of cheese making, was considered a waste product and was pumped into rivers and streams in the U.S. Since the whey contained protein, this practice led to the growth of large concentrations of algae. These were deemed to be a hazard to the ecosystem because they prevented sunlight and oxygen from reaching the water. The government eventually prohibited this practice which led to a disposal problem for producers of other dairy products. Their first solution was to use it as a cheap filler in the production of ice cream. Whey eventually found its way into innumerable other products as a filler and ultimately into a number of health food products where it remains a popular supplement.
Whey protein is commonly marketed as a dietary supplement, and various health claims have been attributed to it in the alternative medicine community. [18] Although whey proteins are responsible for some milk allergies, the major allergens in milk are the caseins. [19] [20]
Whey is the primary ingredient in most protein powders, which are used primarily by athletes and bodybuilders to obtain the necessary amounts of protein for muscle building/maintenance on a daily basis. Whey protein has a high level of leucine, [21] one of the three branched-chain amino acids, making it ideal for muscle growth and repair.[ citation needed ] [22] Whey is pasteurized to assure that no harmful bacteria are breeding in the liquid. It is heated to 70–80 °C (158–176 °F) and is then cooled back down to 4 °C (39 °F). Studies have shown that this process of using extreme temperatures eliminates 99.7% of bacteria without coagulating the protein into a solid mass. Next, the whey must be filtered, and so is loaded into a massive web of ceramic filters and stainless steel turbines. These machines work to separate out the lactose as well as the fats, leaving a liquid of 90% whey protein. [23]
Hydrolysates are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing, but their cost is generally higher. [7] Highly hydrolysed whey may be less allergenic than other forms of whey, [9] due to the fact that the short chain peptides obtained by hydrolysis are less antigenic, because of the elimination of sequential epitopes. [24]
Native whey protein is extracted from skim milk, not obtained as a byproduct of cheese production, and is produced as a concentrate and isolate. [25] [26] [27]
Cream can be skimmed from whey. Whey cream is saltier, tangier, and "cheesier" than ("sweet") cream skimmed from milk, and can be used to make whey butter. Due to the low fat content of whey the yield is not high, with typically two to five parts of butter manufactured from the whey of 1,000 parts milk. [10] Whey cream and butter are suitable for making butter-flavoured food, as they have a stronger flavour of their own. They are also cheaper to manufacture than sweet cream and butter.
Liquid whey contains lactose, vitamins, protein, and minerals, along with traces of fat.
In 2005 researchers at Lund University in Sweden found that whey can help regulate and reduce spikes in blood sugar levels in people with type 2 diabetes by increasing insulin secretion. [28]
Dairy products produce higher insulin responses (Insulin index, II, 90–98) than expected from their comparatively low glycemic indices (GI 15–30). [29] [30] Insulinogenic effects from dairy products have been observed in healthy subjects, both when ingested as a single meal, [31] and when included into a mixed meal. [32] [33] The insulin-releasing capacity of dairy products has been attributed to the protein fraction, particularly the whey fraction, and the subsequent release of amino acids during digestion has been proposed to underlie the insulinogenic properties of milk. [34]
As whey contains lactose, it should be avoided by lactose intolerant individuals. When used as a food additive, whey can contribute to quantities of lactose far above the level of tolerance of most lactose-intolerant individuals. Additionally, people can be allergic to whey or other milk proteins, but as whey proteins are altered by high temperatures, whey-sensitive individuals may be able to tolerate evaporated, boiled, or sterilized milk. Hard cheeses are high in casein, but low in whey proteins, and are the least allergenic for those allergic to whey proteins. However, casein proteins (which are heat-stable) are the most important allergens in cheese, and an individual may be allergic to either or both types of protein. [35]
In 2010 a panel of the European Food Safety Authority examined health claims made for whey protein. For the following claims either no references were provided for the claimed effect or the provided studies did not test the claims, or reported conflicting results: [18]
For the studies around muscle mass and strength whey protein was compared to other protein sources. This is important to note, since protein is necessary for building muscles and this study proved that whey protein is not better for building strength and size than other protein sources.
On the basis of the data presented, the 2010 panel concluded that a cause and effect relationship between the consumption of whey protein and these claims had not been established.
Dairy products or milk products, also known as lacticinia, are food products made from milk. The most common dairy animals are cow, water buffalo, nanny goat, and ewe. Dairy products include common grocery store food around the world such as yogurt, cheese, milk and butter. A facility that produces dairy products is a dairy. Dairy products are consumed worldwide to varying degrees. Some people avoid some or all dairy products because of lactose intolerance, veganism, environmental concerns, other health reasons or beliefs.
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest solid food. Milk contains many nutrients, including calcium and protein, as well as lactose and saturated fat. Immune factors and immune-modulating components in milk contribute to milk immunity. Early-lactation milk, which is called colostrum, contains antibodies and immune-modulating components that strengthen the immune system against many diseases. The US CDC agency recommends that children over the age of 12 months should have two servings of dairy (milk) products a day, and more than six billion people worldwide consume milk and milk products.
Rennet is a complex set of enzymes produced in the stomachs of ruminant mammals. Chymosin, its key component, is a protease enzyme that curdles the casein in milk. In addition to chymosin, rennet contains other enzymes, such as pepsin and a lipase.
Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment, and used as a fat in baking, sauce-making, pan frying, and other cooking procedures.
Casein is a family of related phosphoproteins that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in human milk. Sheep and cow milk have a higher casein content than other types of milk with human milk having a particularly low casein content.
Cottage cheese is a curdled milk product with a mild flavour and a creamy, heterogeneous, soupy texture, made from skimmed milk. An essential step in the manufacturing process distinguishing cottage cheese from other fresh cheeses is the addition of a "dressing" to the curd grains, usually cream, which is mainly responsible for the taste of the product. Cottage cheese is not aged.
Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in Western countries is not made with cultured cream but uncultured sweet cream, most modern buttermilk in Western countries is cultured separately. It is common in warm climates where unrefrigerated milk sours quickly.
Ricotta is an Italian whey cheese made from sheep, cow, goat, or Italian water buffalo milk whey left over from the production of other cheeses. Like other whey cheeses, it is made by coagulating the proteins that remain after the casein has been used to make cheese, notably albumin and globulin.
Cheesemaking is the craft of making cheese. The production of cheese, like many other food preservation processes, allows the nutritional and economic value of a food material, in this case milk, to be preserved in concentrated form. Cheesemaking allows the production of the cheese with diverse flavors and consistencies.
Acid-set or sour milk cheese is cheese that has been curdled (coagulated) by natural souring, often from lactic acid bacteria, or by the addition of acid. This type of cheese is technologically simple to produce.
Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Glycomacropeptide also makes up the third largest component but is not a protein. Whey protein is commonly marketed as a protein supplement, and various health claims have been attributed to it. A review published in 2010 in the European Food Safety Authority Journal concluded that the provided literature did not adequately support the proposed claims.
Calcium caseinate is one of several milk proteins derived from casein in skim and 1% milk. Calcium caseinate has a papery, sweet and overall bland flavor, and is primarily used in meal preparation and fat breakdown. Caseinates are produced by adding an alkali to another derivative of casein, acid casein. The type of caseinate is determined by the cation added alongside the acid casein. Other cations used to form caseinates besides calcium include ammonium, potassium, and sodium.
A milk substitute is any substance that resembles milk and can be used in the same ways as milk. Such substances may be variously known as non-dairy beverage, nut milk, grain milk, legume milk, mock milk and alternative milk.
Goat milk is the milk of domestic goats. Goats produce about 2% of the world's total annual milk supply. Some goats are bred specifically for milk. Goat milk naturally has small, well-emulsified fat globules, which means the cream will stay in suspension for a longer period of time than cow's milk; therefore, it does not need to be homogenized. Eventually, the cream will rise to the top over a period of a few days. If the milk is to be used to make cheese, homogenization is not recommended, as this changes the structure of the milk, affecting the culture's ability to coagulate the milk as well as the final quality and yield of cheese.
Milk allergy is an adverse immune reaction to one or more proteins in cow's milk. Symptoms may take hours to days to manifest, with symptoms including atopic dermatitis, inflammation of the esophagus, enteropathy involving the small intestine and proctocolitis involving the rectum and colon. However, rapid anaphylaxis is possible, a potentially life-threatening condition that requires treatment with epinephrine, among other measures.
Davisco Foods is a company headquartered in Le Sueur, Minnesota. It was founded in 1943. They also own Cambria, the sole producer of quartz work surfaces in the United States.
Milk protein concentrate (MPC) is any type of concentrated milk product that contains 40–90% milk protein. The United States officially defines MPC as "any complete milk protein concentrate that is 40 percent or more protein by weight." In addition to ultrafiltered milk products, the MPC classification includes concentrates made through other processes, such as blending nonfat dry milk with highly concentrated proteins, such as casein.
Whey cheese is a dairy product made of whey, the by-product of cheesemaking. After the production of most cheeses, about 50% of milk solids remain in the whey, including most of the lactose and lactalbumin. The production of whey cheese allows cheesemakers to use the remaining whey, instead of discarding it as a waste product.
Quark or quarg 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.
Sour cream is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. Crème fraîche is one type of sour cream with a high fat content and less sour taste.