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This work presents equilibrium and dynamic aspects for the adsorption at the oil-water interface of pea (Pisum sativum L.) protein isolate (PPI). Dynamic interfacial tension, γ, and surface viscoelasticity modulus, ε, were determined using pendant-drop method. Adsorption kinetics studies revealed that pea proteins adsorb faster at pH 7.0 than at acidic pH (pH 2.4). On the other hand, the measured ε is lower at pH 7.0. This is probably due to fast adsorption, leading to the formation of inhomogeneous film structures. In fact, compared with pHs above the isoelectric point (pI4.3), acidic conditions slow down the adsorption, but the modulus is increased. Pea-protein-stabilized emulsions are more stable to creaming at acidic pH and their particle-size distributions are more homogeneous in these conditions. Effect of pH on interfacial properties and on properties of oil-in-water emulsions stabilized by PPI was interpreted in terms of pea protein solubility, globulin dissociation, and oil-droplet surface electrostatic charge. We propose that at acidic conditions, adsorbed dissociated globulins form stronger and denser viscoelastic networks when adsorbed at oil-water interface. Consequently, the pH-dependence of pea-globulin-stabilized emulsions properties could be of great interest to tune barrier properties of oil/water interfacial membranes for several applications such as encapsulation and controlled release of lipophilic bioactive components within the food, medical, and pharmaceutical industries.

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a b s t r a c tIron supplementation can promote oxidation of food matrices as well as cell lipids. The oxidative stability of oil/water emulsions stabilised by b-lactoglobulin (BLG) or sodium caseinate (SC) was studied in the presence of Fe-bisglycinate, NaFe-EDTA or FeSO 4 . Lipid oxidation was evaluated by following the peroxide value (PV) and the thiobarbituric acid reactive substances (TBARS) over 7 days. At pH 6.5, for Fe-bisglycinate iron complement, the oxidation kinetics was more reduced with BLG than with SC. Contrarily to BLG, SC possesses phosphate groups that have more affinity for iron ions than carboxylate residues. Both BLG and SC stabilised emulsions were more oxidised with Fe-bisglycinate or FeSO 4 than with NaFe-EDTA. At pH 3.5, lipid oxidation was higher compared to pH 6.5. These results indicate that the competition for iron complexation between functional groups of protein and salt counter-ions (glycinate, sulphate or EDTA) appear as a key factor in oxidation.Published by Elsevier Ltd.