Evaluación de la solubilidad de la proteína presente en matrices vegetales: leguminosas, tubérculos y raíces

Abstract

This research was aimed at the evaluation of the protein solubility of different vegetable matrices such as legumes (lupine, firiguero, strawberry bean, parsnip, snap bean), tubers (yellow maca, potato puca shungo), roots (white carrot) and pseudo-cereals (quinoa and amaranth) produced in Ecuador, to be reported as protein solubility index (PSI). This evaluation comprised two steps each one performed using defatted meals. The first step covered the crude protein determination by microkjeldahl and the second included the protein solubilization at pH 8.0 (with NaOH) which was separated from the insoluble components of the meal by centrifugation, and the determination of the protein content in the supernatant by the same method. Crude protein content in the assessed matrices varied between 46.15 percent in lupinus meal and 3.86 percent in White carrot, while soluble protein content ranged from 21.86 and 1.23 percent for the same matrices and the protein solubility index fluctuated between 26.46 percent for amaranth flour and 80.78 percent for firiguero meal. Finally, the amino acid profile in fava flour was evaluated by HPLC analysis performed by a third part accredited laboratory. The results showed that the essential amino acids isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine and histidine accounts for 10.38 grams per 100 grams of the total content while the amino acid with the highest percentage (2.32 grams 100 grams) was aspartic acid. Tryptophan was not analyzed by this laboratory.