Quinoa has been a core crop in the South American Andes Mountains since ancient times. Even today, it continues to be a staple of agriculture in the region, especially in Bolivia, Peru, and Ecuador.
The quinoa plant grows with significant variability and diversity of shapes. The varieties or eco types can be classified into 5 basic categories, according to their adaptation to the geographical characteristics:
- Quinoa from the valley
- Quinoa from the highlands
- Quinoa from saline soils
- Quinoa from sea level and subtropical quinoa
According to this classification, crops of quinoa varieties have been described from sea level (0.0 meters above sea level [masl]) to more than 4,000 masl; however, the optimal development range is between 2500 and 4000 masl. The varieties described at low altitudes are limited to simple forms, without branching and with a very low production of bitter grains. Beck & García (2001), define this as one of the most important agricultural species for the high Andean ecological floor.
The native species and cultivated forms of Chenopodium Quinoa are distributed in the Andes from Colombia to Chile and northern Argentina, in the different altitude ranges described. The main producers worldwide are Bolivia and Peru. Bolivia contributes approximately 43% of world production (CAF et al. 2001).
Some of the highest producing varieties are in the altitude range mentioned above and are located in areas with cooler temperatures. In Bolivia, crops are concentrated in Uyuni, a large part of Oruro, Potosí; and in La Paz, near Lake Titicaca.
It is very important to differentiate the existing varieties of quinoa, since not all varieties have the same amount of saponins, fats, minerals, humidity, or grain size. Sweet quinoa, for example, is slightly smaller compared to the Quinoa Real (reaching 1.8 mm in diameter), and its saponin is not bitter like Quinoa Real.
The difference of the quinoa varieties lies not only in the amount of saponin contained in its grain, but also in the nutritional component that it contains.
The percentage of protein contained in the different varieties of quinoa is shown in Table 2. It shows the lowest percentage of protein with 10.4%, corresponding to the Bolivian Oaslala Quinoa and the highest percentage with 17% corresponding to sweet quinoa from Quitopamba.
Regarding proteins, two basic aspects must be taken into account: quantity and quality. To calculate the amount of protein in the grain, it is necessary to determine the percentage of moisture that quinoa contains. However, this amount is not as important as the efficiency with which the body can use the ingested proteins.
The quality of a quinoa protein is related to the superiority and content of essential amino acids in relation to the proteins in the grains. These essential amino acids can be used for tissue synthesis, once the protein has broken down.
The nutritional value of a protein can be defined as degree by which intake is sufficient in quantity to satisfy the nitrogen requirements of an individual. Also, how well does it satisfy an individuals requirements for each of the essential amino acids needed for the synthesis of tissue proteins.