Food & Beverages

Biography

Biography: Izabel Riegel Vidotti

Abstract

Gum arabic, also known as gum acacia, is a polysaccharide widely used as a food additive. Brazil has one of the largest Acacia mearnsii de Wild (black-wattle) forest plantations, exploited for the extraction of tannin. The gum exudated from the trunks and barks of acacia trees is wasted and seen as a problem for the tannery industry. This work aims to study the emulsifying properties of black-wattle gum as replacer of commercial gum arabic (GAC). For this, black-wattle crude exudates were collected and submitted to two extraction procedures, giving rise to samples (GNF and GNA), which were subsequently characterized and applied in O/W emulsions. For comparative purposes GAC was submitted to the same tests. As result, the polysaccharides GNF and GNA were more efficient in stabilizing the emulsions than GAC. The mass distribution profile of the protein fractions (AGP and GP) and the uronic acid content of the polysaccharides showed to be important factors for their performance. Zeta potential analyses elucidated the mechanism of stabilization in each case. Whereas with GAC the emulsion is stabilized by a combination of steric and electrostatic forces, with GNF the stabilization is achieved mainly by the steric contribution. On the other hand, with GNA several mechanisms are responsible for the stabilization, since a gel-like structure were formed thus reducing the phase separation rate. Therefore, black-wattle gum showed promising results indicating that it can be used as a possible substituent of commercial gum arabic or as a new ingredient in many food formulations.