Soybean Proteins - Lecithin Interaction. Effect of Calcium Salts on the Stability of Oil in Water Emulsions (O/W)

M.C.IACOVELLI; J.R.WAGNER; M.C.TOMÁS

Seattle, WA (USA)

Congreso; 99th AOCS Annual Meeting & Expo; 2008

AOCS

Diverse foods are fortified with calcium salts for improving their composition and to obtain human health benefits. Proteins and phospholipids present interesting surface properties, which enable them to achieve emulsion stability in diverse products. The aim of this work was to study the influence of soybean protein – lecithin interaction on the stability of O/W emulsions in order to evaluate the effect of the presence of calcium salts and the emulsifier agents ratio. Oil in water emulsions were prepared in an Ultraturrax homogeneizer with soybean lecithin (Lec), native isolates (NSI), sunflower oil, protein-lecithin ratio 10:1-10:4 and calcium salts at pH 7.0. The optical characterization of dispersions, the mechanisms of destabilization, kinetics and particle size distribution were determined. NSI - Lec emulsions presented more stability against the addition of calcium salts than those prepared only with Lec. These emulsions recorded a minor stability than systems formulated only with NSI. This fact could be due to the ability of proteins to form a viscoelastic film resistant to the coalescence. The increase of the amount of lecithin in the lecithin-protein ratio produced a diminution of the emulsion stability with the enhancement in particle size. This behavior may be due to the interruption of the stable interfacial film by the inclusion of lecithin and its consequences in the lost of rigidity and viscoelasticity.