Different types of protein

Whey vs Casein protein

Whey → is digested and absorbed faster than other proteins because whey is more acid stable than casein, which results in whey moving from the stomach to the small intestine quickly while casein forms a gel and slows the transit time dramatically / Making casein good for bedtime while whey for workouts

Whey protein is a better option if you want to build muscles. This is because it is quickly absorbed and has slightly more amino acids than casein protein . Whey protein has more of branched chain amino acids (BCAAs), while casein contains more of histidine amino acids, methionine and phenylalanine . Though muscle building requires all the amino acid but leucine that is found in whey protein kick starts the process and thus makes it more important.

Egg protein

There are 8 main proteins in egg whites, including ovalbumin , conalbumin, ovomucoid, avidin, flavoprotein apoprotein, “proteinase inhibitor”, ovomucin, and globulins Protein collectively accounts for about 11-12% of liquid egg white Egg yolk proteins are found in the form of emulsifying lipoproteins due to the high lipid

content of the yolk Egg yolk is rich in fat and consequently egg white has higher protein concentration (gram for gram) than a whole egg or the yolk

Wheat Protein

The four main protein fractions in wheat are albumin, globulin, gliadin, and glutenin , Gliadin and glutenin (are mixed with water, they form gluten, which provides the structural network that allows bread to rise ,Gluten proteins are rich in glutamine and relatively low in lysine, methionine, and tryptophan , Gluten free products have appeared on the market in high amounts during the last decade.

Some individuals have a sensitivity and/or allergic reaction to gluten in the intestine that results in diarrhea and malabsorption issues (gluten sensitive enteropathy)

Soy Protein

Soy proteins are complex multiprotein globulins is a good source of all essential amino acids except methionine and tryptophan , Soy protein isolate (SPI) is used commercially in drinks mixed with fruit and water, coffee whiteners, liquid whipped toppings, and sour cream dressings Soy proteins are often found associated with iso flavone molecules, such as genestein and daidzein, which might have health promoting properties and are considered nutraceuticals (Soy protein isolate is used in some protein supplements and is a more cost effective protein ingredient than whey protein isolate (WPI)

Protein absorption in infants

During infancy, absorption may occur between cells (most occurs by enterocyte pinocytosis .This is particularly important for infants because the fetus does not synthesize antibodies Gamma globulins in the colostrum may be absorbed by the small intestine of the newborn in order to convey passive immunity from the mother during the neonatal period This occurs within the first few hours of birth The subsequent consumption of more mature breast milk proteins eventually limits this activity , Breast milk lactoferrin in infants may also be absorbed by pinocytosis This protein binds iron in breast milk and is thought to promote iron uptake by the infant

Dietary Protein Quality

Protein quality refers to the essential amino acid content in a protein compared with the needs of human cells.

Food proteins that are able to provide all essential amino acids in proportions meeting ,human proteins are called complete proteins or high biological value proteins. High-quality protein (complete protein) → The protein has all nine essential amino acids in proportion to human protein and will support growth and maintenance. Ex. Protein of animal origin. Low-quality protein (in-complete protein) → The protein contains all nine essential amino acids but not in the proportional amounts to meet the body’s need. Plant proteins often fall into this category. Corn is an example because it is low in the amino acid lysine

Reference protein

Several methods are used to assess the relative quality of a protein .Some have advantages, and many of those methods are used in the food industry .The measures used to assess protein quality always compare the quality of a particular protein to a reference protein that is a high quality protein

One such protein that is highly digestible and has an essential amino acid content similar to human protein is egg protein Egg protein is ‘perfect’ protein source for humans in that the correct balance of amino acids appears to be present and available .Another commonly used reference protein is the milk-based protein casein

SOURCE

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3915757/

Stahl W, et al. (2001). Dietary tomato paste protects against ultraviolet light-induced erythema in humans.

https://pubmed.ncbi.nlm.nih.gov/11340098/