Emulsion stabilizers are often surface active agents that are
anchored at the interface between oil and aqueous solution to
reduce surface tension. It was thus verified if tannins were surface
active by measuring surface tension of tannin solution: at the
concentration used in this study, the surface tension was not significantly
decreased, meaning that in our conditions (ionic
strength, pH, concentration), the tannins used in this study were
not surface active (Supplementary data S1).