Protein is one of the three major, or macro, nutrients. Unlike carbohydrates and fats (the other two types of macronutrents), proteins are comprised of nitrogen-containing groups called amino acids. There are about 20 different types of amino acids commonly found in foods. All of them are important for building and maintaining muscle, but 8 are vital. These are what are known as the Essential Amino Acids (EAAs). Contrary to what most athletes believe, there is no actual requirement for protein; the body simply has a requirement for the eight essentials.
Whey protein is derived from milk which is greatly economical, fast acting and is biological available. It has been a famous dietary supplement especially for athletes because it contains numerous components that make it far better than other protein sources. This can further be proven using the Protein Digestibility Corrected Amino Acid Score (PDCAAS) which is a new system that determines the protein quality and is utilized to establish the percent daily value for the nutrients on food labels. The maximum PDCAAS is 1.00, and whey protein got a PDCAAS of 0.99-1.00.
Blended protein powders are made up of any number of different protein sources, such as any type of whey protein (isolates, concentrates, peptides, etc), milk protein isolates, casein, and egg protein.
The benefit to blended protein powders are that by using one, you are receiving a wide variety of amino acid sources. As well, since all of the amino acids are derived from food sources, their nutritional value (vitamin & mineral content) is much higher that a single-source protein like whey protein isolates or concentrates.
Casein protein (pronounced kay-seen) is the predominant protein found in milk. It makes up about 80% of the protein in cow's milk, while the remaining 20% of protein in milk is whey. Casein protein is extracted from the milk through ultra filtration, without the use of chemicals. This process increases the amount of bioactive milk peptides that support immune function as well as enhance muscle growth. Casein protein has an excellent amino acid profile and is primarily known as an extremely slow-digesting protein because it forms a "gel" in the gut, which results in a steady release of amino acids into the blood stream over time. Research shows that when you consume casein, you will reach a peak in blood amino acids and protein synthesis between three to four hours. The total release of amino acids in the bloodstream, however, can last as long as 7 hours after ingestion of casein protein. Whey protein isolate, in comparison, reaches a peak in blood amino acids and protein synthesis in about forty minutes and the total release ends in about an hour.
Alternative protein sources can be a good choice for individuals who want to limit or eliminate the use of animal or milk-based proteins in their diet. Alternative protein sources can consist of non-animal-based proteins such as soy, rice, hemp, chia, cranberry, and even sea vegetation like spirulina (an algae). However, we can also consider egg or beef (yes, BEEF) protein powders as alternative sources, since they are not derived from milk. Vegans and vegetarians can benefit from consuming some of these proteins, due to their excellent amino acid profiles, and unique tastes.