Cooking effects on iron and proteins content of beans (Phaseolus Vulgaris L.) by GF AAS and MALDI-TOF MS

Abstract

Os efeitos do cozimento doméstico na distribuição de proteínas, compostos orgânicos e Fe em feijão (Phaseolus vulgaris L.) foram investigados. Extração seqüencial com diferentes agentes extratores (mistura de metanol e clorofórmio 1:2 v/v, água, NaCl, etanol e NaOH) foi usada para extrair lipídeos, albuminas, globulinas, prolaminas e glutelinas, respectivamente. A determinação de Fe por espectrometria de absorção atômica com forno de grafite (GF AAS), de proteínas pelo método de Bradford e compostos orgânicos por espectrometria de massas por tempo de vôo acoplada à ionização dessortiva de matriz por laser (MALDI-TOF MS) foram feitas nesse trabalho. Altas concentrações de albuminas, globulinas e glutelínas foram encontradas em feijão cru, enquanto que em grãos cozidos, albuminas e glutelínas foram os principais tipos de proteínas. Os espectros de MALDI-TOF MS do feijão cru e cozido revelaram que o cozimento doméstico alterou os pesos moleculares dos compostos orgânicos, uma vez que nos grãos cozidos foram encontrados compostos entre 2 e 3,5 kDa, os quais não estavam presentes no feijão cru. Além disso, no feijão cozido foi também observada a presença de quatro compostos de alto peso molecular (12-16 kDa), sendo que em grãos crus há somente um (ca.15,2 kDa). Nos grãos crus foi possível observar que Fe está principalmente associado a albuminas, globulinas e glutelínas. Para os grãos cozidos, Fe está presente em alta concentração em albuminas e globulinas.The effects of domestic cooking on proteins, organic compounds and Fe distribution in beans (Phaseolus vulgaris L.) were investigated. Sequential extraction with different extractant solutions (mixture of methanol and chloroform 1:2 v/v, water, 0.5 mol L -1 NaCl, 70% v/v ethanol and 0.5 mol L -1 NaOH) were used for extracting lipids, albumins, globulins, prolamins and glutelins, respectively. Iron determination by graphite furnace atomic absorption spectrometry (GF AAS), proteins by Bradford method and organic compounds by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) were carried out in this work. High concentration of albumins, globulins and glutelins were found in raw beans, while in the cooked beans, albumins and glutelins are main proteins types. The MALDI-TOF MS spectra of raw and cooked beans revealed that the domestic cooking altered the molecular weight of the organic compounds, since that in the cooked beans were found compounds between 2 and 3.5 kDa, which were not presented in the raw beans. Besides this, in cooked beans were also observed the presence of four compounds of high molecular weight (12-16 kDa), being that in the raw grains there is only one (ca. 15.2 kDa). In raw grains is possible to observe that Fe is mainly associated to albumins, globulins and glutelins. For cooked grains, Fe is associated to albumins and globulins.

Protein and Metalloprotein Distribution in Different Varieties of Beans (Phaseolus vulgaris L.): Effects of Cooking

“…The main amino acids constituents of albumins, globulins, prolamins, and glutelins are rich in sulfur and charged groups that present high affinity by metal ions [8]. Heating may result in the denaturation of the proteins.…”

“…High concentrations of albumins, globulins, and glutelins have been found in raw beans [8]. Salt-soluble globulins, which constitute 34 to 81% of the total protein content, are rich in leucine, lysine, glutamine, and asparagine [5].…”

Effects of Iron Enrichment of Adzuki Bean (Vigna angularis) Sprouts on Elemental Translocation, Concentrations of Proteins, Distribution of Fe-Metalloproteins, and Fe Bioaccessibility

“…The main amino acids in albumins, globulins, prolamins, and glutelins, such as methionine, cysteine, glutamic acid, arginine, aspartic acid, and lysine, are rich in sulfur and charged groups. [45][46][47][48] These amino acids have high affinity for ions of transition metals, such as Fe. 49 It is important to point out that the fractionation experiments in this work are the first step toward nutritional information about Fe-enriched adzuki bean sprouts.…”

Effects of the Domestic Cooking on Elemental Chemical Composition of Beans Species (Phaseolus vulgaris L.)

“…Brazil is the largest worldwide producer (2.2-2.5 million tons on approximately 5 million hectares cultivated) and consumer (around 16 kg per capita) of beans [1][2][3]. The Brazilian food pyramid shows beans in a group of their own, and the Food Guide for the Brazilian Population recommends the consumption of at least one portion of beans per day [4].…”

“…The Brazilian food pyramid shows beans in a group of their own, and the Food Guide for the Brazilian Population recommends the consumption of at least one portion of beans per day [4]. Beans are one of the main protein sources for Brazilians [1][2][3].…”