Interfacial mechanisms regulating lipid digestion: a systematic study using tween surfactants with varying structural features

This study systematically investigated the crucial interfacial mechanisms regulating lipid digestion using Tween surfactants with varying structural features. In vitro digestion revealed that, Tween 40/Tween 60 strongly inhibited, Tween 20/Tween 80 significantly delayed, while Tween 81/Tween 85 minimally affected lipid digestion. Tween surfactants modulated lipid digestions primarily by competing with bile salts for interfacial adsorption rather than inactivating the lipase. The emulsifiers with appropriate hydrophilic and lipophilic balance (HLB) and small critical packing parameter (CPP), like Tween 40/Tween 60, anchored to the interface and provided steric hinderance, thus inhibited the displacement by bile salts. In addition, those interfacial layers that inhibited the diffusive exchange of amphiphiles between the interface and the bulk phase, but maintained viscoelasticity through molecular conformational rearrangement or lateral molecular reorganization, could inhibit the bile salts adsorption and thus modulate lipid digestion effectively. These findings established interfacial design principles for tailored lipid digestion control in food emulsions.