EFFECT OF CITRIC ACID ON PHYSICAL STABILITY OF SUNFLOWER OIL-IN-WATER EMULSION STABILIZED BY GELATINIZED BAMBARA GROUNDNUT FLOUR

The influence of citric acid concentrations on the physical stability of sunflower oil-in-water emulsions (40 w/w% sunflower oil) stabilized by 7 w/w% bambara groundnut flour (BGNF) was investigated. Oil droplet sizes and emulsion microstructure were measured microscopically. Physical stability was studied using a vertical analyzer, Turbiscan MA 2000, by observing changes in backscattering flux (%) at 20oC. Citric acid significantly (p < 0.05) affected emulsion stability of BGNFstabilized emulsion. Increased citric acid in the emulsion however, produced insignificant difference in droplet size and physical instability of BGNF-stabilized emulsions at all tested concentrations. The results indicated that the stability of BGNF-stabilized emulsion can be controlled and manipulated using citric acid. The result provided the necessary information needed to understand the influence of citric acid on the stability of BGNF-stabilized emulsions for product and process development