Identification, determination and bioavailability evaluation of elements binding to metaloproteins in nuts

• Grant number: 07/03275-0
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2007
• End date: July 31, 2009
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Pedro Vitoriano de Oliveira
• Grantee: Pedro Vitoriano de Oliveira
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The aim of this project is the identification, determination and bioavailability evaluation of essentials (Cu, Fe, Mn, Se e Zn) and toxic elements (Cd, Hg, Ni e Pb) binding to metalloproteins of different nuts (Brazil nut, coconut, cupuassu seed, babaçu, castanha de caju, etc). The specific objectives are related to different projects in progress in the research group. Total concentration of these elements will be determined by graphite furnace atomic absorption spectrometry and inductively-coupled plasma optical emission spectrometry after digestion in closed-vessel microwave oven. Protein groups will be extracted from samples using solid-liquid extractions with different extractants (H2O, NaCl solution, ethanol, NaOH solution, tris-HCl buffer, etc) after lipids and oils separation using a mixture of methanol + chloroform and/or centrifugation. The bioavailability of elements will be studied in vitro using simulated digestions for stomach, with gastric fluid (pepsin + HCl) and intestinal digestion (pepsin + HCl, pancreatin e pancrease). The proteins extracted before and after the simulated digestion will be separated in size exclusion chromatography and detected by UV-vis. The eluted solution will be collected in micro-vials and the elements determined by graphite furnace atomic absorption spectrometry. Proteins will be identified by mass spectrometry. (AU)