Quinoa: protein and nonprotein tryptophan in comparison with other cereal and legume flours and bread

• nutritional value of bread can be improved making composite flours with non wheat cereals or supplementing its flour with protein-rich sources, such as legume flours, especially in the several countries where the production of wheat is insufficient; • quinoa can be an alternative to cereals in the human diet for its nutritional value and high good quality proteins similar to those of milk, and for these reasons, its use should be promoted to enrich the nutritional value of bakery products; • tryptophan is present in cereals and legumes not only as protein tryptophan but also as non protein tryptophan (Figure 7); • non protein tryptophan should be taken into account when the nutritional value of a food is determined; • the determination of non protein tryptophan in cereals and legumes is very important since this fraction is easily absorbable at the gastrointestinal level increasing its availability for brain serotonin synthesis.