Formación y estabilidad de emulsiones de aislados proteicos de soja con diferente contenido de sulfhidrilos libres Formation and stability of emulsions of soy protein isolates with different sulfhydryl content
This work evaluated the formation and stability of emulsions prepared with three soy protein iso lates with different sulfhydryl content (SHL) and at two different pHs (6.00 and 7.00). Solubility (Sol), emulsifying activity index (IAE), coalescence (%Coal), surface concentration of proteins (r), and ki netics of the creaming process were determined. The effects of pH and sample types or their interac tion were significant (p < 0.05) for the four variables. IAE was little enhanced by the SHL increment, while stability to coalescence decreased. Also, it was verified that Γ is negatively affected by the SHL increment. The pH effect on IAE depended on the SHL. When pH decreased, %Coale lowered and Γ increased. Emulsions destabilized by the floculation-creaming mechanism more slowly at pH 6.00 than at pH 7.00.