Brea gum as wall material for encapsulation of hydrophobic compounds or controlled release applications

EMILIANO BUSEGHÍN; MARIA VIRGINIA CASTEL; ANDREA PIAGENTINI; CARLOS ROBERTO CARRARA; AMELIA CATALINA RUBIOLO

Concordia, Entre Ríos

Conferencia; International Conference on Food Innovation, Food Innova; 2014

International Conference on Food Innovation, Food Innova

Brea gum (BG) is an exudate obtained from Parkinsonia praecox trees that grows in Salta (Argentina). This hydrocolloid is similar to gum Arabic (GA), consisting in 83.77% polysaccharides and 7.5% proteins. Hydrocolloids are typically used not only as rheology control and stabilizating suspending agents but also as structured carriers for controlled release and encapsulation applications. In this context, BG is a biopolymer that represents an interesting alternative to synthetic polymers as it is a biocompatible and biodegradable hydrocolloid. In this study, spray drying encapsulation using BG as wall materials was tested in comparison with a comercial GA. BG exudate nodules were purified by dissolution, centrifugation, filtration and freeze-drying steps. Then, BG solutions (5%, 10% and 20% w/w) and a 20% w/w GA solution were used to emulsify pure corn oil in a 10:1 proportion with a Polytron homogenizer blending (Polytron, Kinematica, Bohemia, NY, USA) followed by an ultrasonic treatment (Ultrasound generator, Sonics and Materials VC-750, Newton, CT). Emulsions were spray dried in a laboratory scale equipment (Spray Dryer, ADL311 Yamato). The morphology and microstructure of the powders was observed by scanning electronic microscopy (JSM-35C, JEOL, Tokyo, Japan). Powders´ water activity was measured with a team Aqua-Lab Water Activity Meter and moisture content was determined gravimetrically by drying in a vacuum oven at 70 °C until constant weight. Color analysis was performed in a colorimeter (Minolta 508d). Encapsulation efficiency (EE) was calculated from the ratio between the amount of encapsulated oil and total oil present in the powders determined by gravimetric methods. All the powders presented similar external morphologies: capsules of spherical shape with no apparent cracks or porosity with sizes varying between 0.6 and 26 µm. This implies that capsules have low permeability to gases, increasing protection and retention of the core material. In general, samples did not show significant differences in moisture content (around 1.5%) or water activities (around 0.3) when different GB concentration or GA solutions were used. GB powders presented lower luminosity and more red and yellow parameters than GA powder as the color analisys showed. EE increased with GB concentration, reaching 71.32% of efficiency with the 20% GB solution wich was in the range of the EE achieved with 20% GA (88.44%). According to this results, GB could be suggested as a good wall material alternative for microencapsulation of hydrofobic compounds, which could replace GA.