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Chromatographic fractionation and molecular mass characterization of Cercidium praecox (Brea) gum
Author(s) -
Castel Virginia,
Zivanovic Svetlana,
JuratFuentes Juan L,
Santiago Liliana G,
Rubiolo Amelia C,
Carrara Carlos R,
Harte Federico M
Publication year - 2016
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.7642
Subject(s) - fractionation , size exclusion chromatography , molecular mass , chromatography , polysaccharide , chemistry , fraction (chemistry) , gel permeation chromatography , chemical composition , elution , chemical structure , exudate , molar mass distribution , biochemistry , organic chemistry , botany , biology , enzyme , polymer
BACKGROUND Brea gum ( BG ) is an exudate from the Cercidium praecox tree that grows in semi‐arid regions of Argentina. Some previous studies on BG have shown physicochemical characteristics and functional features similar to those of gum arabic. However, there is a need to elucidate the molecular structure of BG to understand the functionality. In this sense, BG was fractionated using hydrophobic interaction chromatography and the obtained fractions were analyzed by size exclusion chromatography. RESULTS Analysis of the fractions showed that the bulk of the gum (approx. 84% of the polysaccharides) was a polysaccharide of 2.79 × 10 3 kDa. The second major fraction (approx. 16% of the polysaccharides) was a polysaccharide–protein complex with a molecular mass of 1.92 × 10 5 kDa. A third fraction consisted of protein species with a wide range of molecular weights. The molecular weight distribution of the protein fraction was analyzed by size exclusion chromatography. Comparison of the elution profiles of the exudates in native and reducing conditions revealed that some of the proteins were forming aggregates through disulfide bridges in native conditions. Further analysis of the protein fraction by SDS‐PAGE showed proteins with molecular weight ranging from 6.5 to 66 kDa . CONCLUSIONS The findings showed that BG consists of several fractions with heterogeneous chemical composition and polydisperse molecular weight distributions. © 2016 Society of Chemical Industry