Preparation And Functional Properties Of Gum Arabic Rich In Trace Elements

Gum arabic (GA) is an exudate from Acacia tree and it has been widely used asstabilizer and emulsifier in the food industry. Se, Cu, Zn, and Fe, as trace elements,play important roles in human health. High dose of Se is necessary for its anticancerfunction, which also results in high toxicity. The toxicity of Se is significantly reducedwhen it is in nanosize range. The efficient delivery and absorption of Cu, Zn and Feby human bodies prove to be challenging. Incoporation of those trace elements intoGA can be one of the approaches to trackle the problem. In the work, GA was used toprepare SeNPs. The stabilizing mechanism, antioxidant properties of SeNPs in the GAaqueous solutions, and their application in emulsions were studied. Trace elements(Cu, Zn, Fe) were incorporated into GA by ion exchange method. The emulsifyingperformance of the trace elements-rich GA (GACu2+, GAZn2+, GAFe3+, GAFe2+) wasinvestigated. Conclusions are as follows:1. GA could effectively stabilize SeNPs. The as-prepared SeNPs had a diameterof~35nm while the size of GA-SeNPs composite was~140nm. The particle size wasreported to be within the size range that could enhance antioxidant ability and cellularuptake of Se. pH had negligible effect on the size of SeNPs. The nanoparticles werestable without precipitation in GA aqueous solutions for up to30days. FTIRdemonstrated that GA and SeNPs were combined via hydroxyl group and GA wasphysically adsorbed on to the surface of SeNPs. The stability of SeNPs in GA aqueoussolutions was closely related to the branched structure of GA, hydroxyl groups, andparticle size.2. Protein content was the major factor that influenced the antioxidant propertiesof GA-SeNPs composite. With comparable content of protein, arabinogalactan-proteincomplex (AGP) could determine the antioxidant properties. At a concentration of4mg/ml, the hydroxyl radical and DPPH radical scavenging ability of GA-SeNPs were85.3±2.6%and85.3±1.9%, respectively.3. SeNPs could be successfully incorporated into GA-stablilized emulsions andwere stable for up to3days during acceleration test at60oC.4. GA rich in Cu, Zn, and Fe was successfully prepared by ion exchange method.Introduction of the ions increased the moledcular weight and AGP content of GA withthe order: GAFe2+> GAFe3+> GAZn2+> GACu2+> GA. The emulsions stabilized by the different GA had increased emulsion stability: GAFe3+> GAZn2+> GA> GACu2+>GAFe2+.The stability was closely related to molecular weight, AGP and interfacialproperty.