Probing the Acid-Induced Hydrolysis of Sucrose Monopalmitate and Its Role in Interfacial Properties

The hydrolysis of surfactants in acidic environments has been overlooked when evaluating their functionality. This gap is addressed here by investigating the breakdown of sucrose monopalmitate (SMP) on both ester and glycosidic bonds. As the main pathway, glycosidic hydrolysis generated reducing sugars and monosaccharide monopalmitate; ester hydrolysis was minor. The first-order kinetics were accelerated at low pH and elevated temperatures. At pH 3 and 20 °C, 10 w/w% SMP was hydrolyzed after 4 weeks. After hydrolysis, surfactants showed higher hydrophobicity, inhibited interfacial adsorption, enlarged micelle sizes, promoted aggregation, and a lower critical micelle concentration. These changes reduce the elasticity of the interface, thereby undermining foaming and emulsifying activities but inhibiting lipid oxidation. Emulsions initially stabilized with SMP (pH 3) exhibited droplet growth during storage, which was attributed to disruptions in the oil-water interface as the disaccharide-based polar head is cleaved. These findings reveal the critical role of changing the molecular characteristics of emulsifiers to tune their interfacial behavior.