The protein powder is a food supplement that not only could we rightly classified as that to more widespread use, but also one of the first in terms of personal marketing.
To be synthesized by the body, proteins need simpler structures called amino acids, that as real rings are combined to form protein filaments.
In nature the amino acids are divided into 2 groups:
Essential amino acids: are those that our body cannot synthesize autonomously and then taken through food
Non-essential amino acids: are those that our body can synthesize on its own

What is the difference makes food and protein powder? they assimilate better?
Confirmation that the protein from supplements have a better assimilation is to try, but what is certain is they have absorption rates significantly faster and this is one of the reasons that makes them functional in sport.
However, there are quite varied and products that match different needs or situations:

WHEY PROTEIN

These proteins have a very high biological value (100) and is obtained by separating whey from curds.
Are absorbed very quickly and are therefore useful in times when the body needs nourishment immediately (in the morning, pre or post workout especially)

CASEIN PROTEIN

Casein is instead derived from the treatment of rennet, has a lower biological value to previous (80) and requires a greater digestion time (from 4 to 6 hours). It is widespread its use before bedtime, in order to limit the phenomena arising from catabolic fasting during sleep.

EGG PROTEIN

These proteins have a very high biological value (100) and assimilation time short. The best time to take it is to be considered in the post workout. The presence of arginine within themselves in fact encourages the increased insulin production, useful to limit the catabolic effects
SOY PROTEIN

Probably the most recent product marketing. They do not have a high biological value (75)
Among the uses that are worth mentioning as part of bodybuilding which would see a viable product in the definition phase. It seems that these proteins affect the production of thyroxine, so keep up your metabolism even during low-calorie diets.

Roberto