All the protein you eat will not get converted to body proteins.
The proteins which we ingest in our diet will get hydrolysed in our digestive tract, and the amino acids released will be absorbed and taken to cells of various parts of our body where new proteins are synthesized. Our body can synthesize 11 amino acids only and we must get the rest ,10, from our diet. These 10 amino acids which should be “essential” components of food are known as essential amino acids. They are so important in protein synthesis (protein makes up to 50% of dry matter of protoplasm) that in absence of any of these 10 amino acids, no new protein is synthesized and the amino acids get deaminated to carboxylic acids and used as energy sources.
They are the following :
M – Methionine
I – Isoleucine
L – Leucine
L – Lysine
P – Phenyl alanine
A – Arginine
T – Tryptophan
H – Histidine.
T – Threonine
V – Valine
You can remember them by the acronym“Millpath TV”.
Non-vegetarian food like meat, eggs, and milk, are complete proteins containing all of the essential amino acids. But for strict vegetarians the easiest source is pulses. Pulse proteins are much better for maintenance and building up of body because of three reasons: 1. they contain all the 10 “essential amino acids”, 2. are easily soluble in water and thus easily digestible and 3. are not destroyed by cooking. In absence of any of these 10 amino acids, no new protein is synthesized and the amino acids get deaminated to carboxylic acids and get into respiratory stream.
2. Proteins in pulses are mostly (up to 80%) albumins (soluble in water) and globulins (soluble in salt solutions) always predominate over prolamines and glutelins ( both insoluble in water or salt solutions, but only soluble in dil. acid/alkali/70-90% alcohol). Although the ratio of globulin to albumin varies in different seeds, globulins are the major proteins. In Vicia faba, 80% of the total protein consists of globulins and albumins while glutelins form 15% and prolamines less than 5%. This ratio is closely followed in majority of pulses.
3) Unlike cereal proteins, the pulse proteins are not destroyed by cooking or in other words there is no Maillard or Browning reaction in which certain amino acids like lysine in proteins react with carbohydrates (starch)to form insoluble (indigestible) complexes.
Another source of essential amino acids are the leaves of certain plants like spinach (Spinacia oleracea-2.9%), cauliflower (1.9%), Asparagus shoots (young- 2.2%) and broccoli (2.8%). It is to be remembered that all leaves contain useful proteins, albeit, in small amounts.
In contrast to this, cereal proteins contain only 7-8 essential amino acids resulting in reduction in protein synthesis. The gluten which forms 70-80% of storage proteins in Barley, corn and wheat is a combined aggregate of prolamines and glutelins in the ratio of 1:1. The remainder of seed proteins in these grains consists of 50% albumins and globulins. In rice, the major group of protein is glutelins (50%) and the rest consists of equal quantities of albumins, globulins and prolamines. Oats is the only exceptional cereal in that the major protein is globulin and contain all essential amino acids. Cereal proteins undergo Maillard or Browning reaction in which amino acids like lysine (with an extra amino group) in proteins react with carbohydrates (starch) to form insoluble (indigestible) complexes making it unavailable for our body.
Source :
Useful Herbs of the Planet Earth, by M. Daniel, (2012), Scientific Publishers, Jodhpur, INDIA.
Mammen Daniel
