Whey Protein

The liquid remaining after milk has been curdled and strained is known as whey.

Updated: June 16, 2022

The liquid remaining after milk has been curdled and strained is known as whey. It is a byproduct of the manufacture of cheese or casein.
Sweet whey is a byproduct produced during the manufacture of rennet types of hard cheese, like Cheddar or Swiss cheese where as Acid whey or sour whey is a byproduct produced during the making of acid types of dairy products, such as cottage cheese or strained yogurt. Sweet whey has a pH greater than or equal to 5.6 and acid whey has a pH less than or equal to 5.1.
Whey proteins consist of alpha-lactalbumin, beta-lactoglobulin, serum albumin, immunoglobulins, and proteose-peptones. These are soluble in their native forms, independent of pH. Cow's milk consist of 20 percent whey protein and 80 percent casein protein, whereas human milk consist of 60 percent whey and 40 percent casein.
The amino acid cysteine in whey protein helps in the synthesis of glutathione in the body which is a ubiquitous cellular antioxidant.

Preparation Of Whey Proteins:

Rennet or an edible acid is added to heated milk to make cheese. The edible acid makes the milk coagulate or curdle and separate the milk solids (curds) from the liquid whey. Whey contains everything that is soluble from milk after the pH is dropped to 4.6 during the process of coagulation. The solution contain 5 percent of lactose in water, with some minerals and lactalbumin.
The fat is removed and then processed by simple drying. The relative protein content can be increased by removing lipids and other non-protein materials. For example, after membrane filtration spray drying separates the proteins from whey. Whey can be denatured by heat. Heat-denatured whey can still cause allergies in some people.

Uses Of Whey Proteins:

Whey is used to produce whey cheeses such as ricotta, brunost, and whey butter and many other products for human consumption. It is also an additive in many processed foods, including breads, crackers, and commercial pastry, and in animal feed. Whey is used in number of health food products where it remains a popular supplement. Those taking whey protein can gain more kilograms of muscle mass than people taking the other supplements.
Soy protein and Pea protein are alternatives for those who choose not to consume animal protein or are lactose intolerant. Whey protein is commonly marketed as a dietary supplement and is sold as a nutritional supplement, which are especially popular in the sport of bodybuilding. Whey is the primary ingredient in most protein powders, which are used primarily by athletes and bodybuilders to obtain the necessary amounts of protein on a daily basis.
Whey protein has a high level of leucine, which is important for muscle growth and repair.

Types Of Whey Proteins:

Whey protein typically comes in four major forms. This include concentrate (WPC), isolate (WPI), hydrolysate (WPH) and Native Whey.

Concentrates whey proteins have typically a low level of fat and cholesterol. They are higher in carbohydrates in the form of lactose compared to the other forms of whey protein. By weight they have 29 percent to 89 percent protein.
Isolates whey proteins are processed to remove the fat and lactose. whey protein isolates are mild to slightly milky in taste and they contain 90 percent + protein by weight.
Hydrolysates whey proteins are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing. Highly hydrolysed whey may be less allergenic than other forms of whey. These are high in cost compared to the other forms of whey protein.
Native whey protein is extracted from skim milk, not a byproduct of cheese production, and produced as a concentrate and isolate.

Health Effect Of Whey Proteins:

Whey should be avoided by those who are lactose intolerant as it contains lactose.
Dried whey contains 65-75 percent lactose and 11-12 percent protein where as Liquid whey contains lactose, vitamins, protein, and minerals, along with traces of fat.
Whey proteins can help regulate and reduce spikes in blood sugar levels in people with type 2 diabetes by increasing insulin secretion.
People can be allergic to whey or other milk proteins.
Whey-sensitive people may be able to tolerate evaporated, boiled, or sterilised milk as whey proteins are altered by high temperatures.
Whey has also some other health benefits which are not been tested. These include:

Increase in satiety leading to a reduction in energy intake
Contribution to the maintenance or achievement of a normal body weight
Growth or maintenance of muscle mass
Increase in muscle strength
Increase in endurance capacity during the subsequent exercise bout after strenuous exercise
Increase in lean body mass during energy restriction and resistance training
Reduction of body fat mass during energy restriction and resistance training
Skeletal muscle tissue repair
Faster recovery from muscle fatigue after exercise.