Caracterización de Aislados proteicos de quinua (Chenopodium quinoa Willd) y su Digestibilidad gástrica y duodenal (in vitro)

Abstract

This study was based on the characterization of quinoa protein isolates (Chenopodium quinoa Willd.) and evaluation of its gastric and duodenal in vitro digestibility of defatted quinoa flour. The isolates were obtained at pH 2.0; 3.0; 4.0; 5.0 and 6.0. Best yield was obtained in quinoa protein isolate obtained at pH 4.0 with 6.29 percent more less 0.03, showing a content of protein of 64.97 percent more less 0.13. The content of protein in all isolates was higher than 50 percent. The isolate quinoa protein was characterized by SDS-PAGE. The presence of 7S globulin, 11S globulins (acidic and basic subunit) and 2S albumin were observed. Subsequently, the quinoa protein isolates were hydrolyzed with pepsin 1/20 (SGF) at pH 1.2; 2,0; 3.2; 4.5 and 5.5. These samples were analyzed by SDS-PAGE electrophoresis. The proteins were completely hydrolyzed at pH 1.2 and at pH 2.0 after gastric hydrolysis. At pH 4.5 and 5.5 proteins of quinoa present resistant to hydrolysis with pepsin. After duodenal hydrolysis with a cocktail of proteolytic enzymes (chymotrypsin, trypsin, lipases, colipasas) proteins were completely hydrolyzed. Quinoa hydrolysates at pH 1.2 showed no antioxidant activity at the tested conditions with ORAC method. RP-HPLC analysis of quinoa protein isolated at pH 4.0 showed appearance of chromatographic peaks between 5 and 65 minutes. The chromatographic profile was very complex as separation was not performed with the analytical definition of the different proteins of isolated.