Purification of seed storage proteins of Quinoa for nanotechnological applications

HERNÁN BURRIEZA; OSCAR E PÉREZ; FRANCISCO VELÁZQUEZ DUARTE; PILAR BUERA; JIMENA H MARTÍNEZ; FEDERICO COLUCCIO-LESKOW

Buenos Aires

Simposio; Frontiers in Physical Sciences; 2016

Centro de Latinoamericano de Formación Interdisciplinaria y MinCyT.

Quinoa (Chenopodium quinoa Willd.) seeds are contained into fruits composed of a saponin rich pericarp surrounding a starchy disc shaped perisperm which is encircled by an oil and protein rich embryo. These seeds are rich in protein with an average content of 12.6% in dry weight. 11S globulin is one of its major storage proteins and is eligible for control delivery of bioactives by molecular self-assembly nanoencapsulation, a spontaneous and specific association of molecules dictated by non-covalent interactions. In the present study we obtain highly purified 11S globulin from quinoa seeds which would be used as encapsulating material in nanocarriers with biomedicinal and cosmetic applications.Quinoa flour was obtained by grinding whole seeds in a mill, suspended in hexane 10% (w/v) and defatted for 24 h. The protein content in the flour (17% w/w) was determined by the micro-Kjeldhal method. Defatted flour was stirred in extraction buffer, centrifuged and the supernatant was preserved. After that, pH was adjusted to 5 and an 11S enriched precipitate was obtained. The precipitate was collected by centrifugation, resuspended in extraction buffer and subjected to gel filtration chromatography using a Superdex 200 10/300 GL for a high-resolution separation of 11S according its size in a FLPC. Chromatogram showed several peaks corresponding to different storage proteins. Fractions were analyzed by SDS-PAGE (10%) with and without beta-mercaptoethanol. A highly enriched 11S fraction displaying the characteristic band pattern upon reductive treatment was obtained (basic and acidic monomers, 17 y 30 KDa respectively). We also detected other proteins in this fraction (53 and 35 KDa) and MALDI-TOFF analysis was performed.In the present work we show a detailed 11S isolation protocol, which renders a pure protein as the first step in self-assembly approaches for nanoencapsulation applications aimed to carry key molecules for exerting controlled delivery. We also report novel putative storage proteins in quinoa seeds.