Effect of Sodium Caseinates on Emulsion Stabilizing Property of Soy Proteins

Studies on the Emulsifying Properties of Soybean Proteins, Part IX

Abstract

Stabilization mechanism of a series of protein stabilized emulsions was investigated by determining oil globule size distribution and protein load^* of emulsions. Oil globule size distribution in the acid-precipitated soy protein (APP)-stabilized emulsions was shifted by mixing APP with sodium caseinate (SC) toward larger range in the case of agitation emulsification, and shifted toward smaller range in the case of ultrasonic emulsification, respectively. These results agreed with change in emulsion stabilizing property of APP caused by mixing APP with SC. In both ultrasonic and agitation emulsification, surface of oil globules in the emulsions stabilized with the protein mixtures was coated with SC alone. Protein load of SC in the emulsions stabilized by sonication was found to be generally larger than that in the emulsions stabilized by agitation method. ^*Amount of proteins adsorbed onto unit surface area of oil globules, mg/mm².