Legume proteins: what do you need to know?

Legumes: what are they?

In the food sector, by legumes we mean foods of vegetable origin consisting of edible seeds such as chickpeas , lentils , peas , beans, broad beans , soybeans , lupine, grass peas .

In the Mediterranean diet , legumes play a role of primary importance: they should in fact be consumed at least twice a week in considerable portions, for example as a first course, even in the form of legume flour pasta.

Furthermore, they are a source of starch – therefore calories -, medium biological value proteins , “good” fats, group B vitamins , minerals ( iron , calcium , magnesium , phosphorus , potassium ) and other beneficial nutritional factors ( fibers , lecithins , phytosterols ).

Raw ones contain potentially anti-nutritional molecules, which however are partially eliminated by soaking them – in the case of dry ones – or in any case denatured by cooking.

Protein

What are proteins

From a chemical point of view, proteins are large and complex biological molecules, made up of one or more chains, in turn made up of “building blocks” called amino acids . There are innumerable types of proteins, with equally infinite biological functions.

Protein functions

Some of the main tasks performed by proteins in living organisms (animals, plants, fungi, bacteria ) include hormonal signaling and neurotransmission, cellular DNA replication , response to stimuli, immune response, cellular and tissue structure, transport of molecules.

Protein synthesis

There are specific cellular structures responsible for the synthesis of proteins, which are first involved in linking the amino acids together respecting a specific sequence and possibly in relating the various chains.

Organisms possess the ability to synthesize the necessary proteins, provided however that the “bricks” necessary for the construction of these chains are obtained through food .

Amino acids and biological value

Not all amino acids are the same, nor are the proteins they make up.

Essential and non-essential amino acids

There are 20 amino acids that structure proteins: a part of these is of the essential type, that is, given the inability to produce them independently, they must necessarily come from food. The remainder are non-essential, and can be synthesized from the essential if necessary.

For many years there was a debate about which ones were essential and which ones were not. The problem is that the synthesis capacity of some of them can change according to age and other conditions (genetic diseases, wounds and burns , etc.). Today it is believed that there are 12 essential amino acids .

Biological Value (VB)

The biological value is therefore the only “qualitative” parameter to really take into account.

Divided into high, medium and low, this index translates into a number that can be placed on a scale from 0 to 100, which allows you to establish the amount of protein actually absorbed and used by the body.

The proteins with the greatest biological value are of animal origin, i.e. eggs , milk , meat and fishery products . Not surprisingly, to ensure that nutritional needs are met, it is generally recommended that at least two thirds of total protein comes from animal sources.

On the other hand, it is always a good idea to consider that what matters is the amount of amino acids taken, i.e. the units indispensable to the composition of proteins. In this sense, the vastness of proteins of vegetable origin means that, by combining or alternating them correctly, it is possible to compensate for the lack of one or more essential amino acids which characterizes these nutrients.

Legume protein

Speaking of vegetable proteins , those of legumes are not complete and are deficient especially in two amino acids, methionine and cysteine . On the other hand, cereal proteins are generally sufficiently rich in these two units, but are poor in lysine and tryptophan , instead adequately supplied by legume proteins .

This is why, from the point of view of the protein profile, the combination of legumes and cereals is a winner.

Macronutrients

Dietary proteins are considered true nutrients and, more precisely, macronutrients .

The etymological root “macro” (large) refers to the quantity in which these nutrients must be introduced. The total protein requirement is in fact several grams per day (g/day).

Protein requirement

The diet must always contain a minimum amount of protein, which in a healthy sedentary adult is around 44-55 grams g/day, or about 0.8 g per kilogram of ” normal” body weight (g/kg) – the the maximum recommended limit, on the other hand, is about double. During growth and with particularly high levels of physical activity, the requirement can increase significantly.