Improving the emulsifying properties and oil–water interfacial behaviors of chickpea protein isolates through Maillard reaction with citrus pectin

Abstract

The limited adsorption capability of chickpea protein isolates (CPI) at the oil–water interface restricts its application in emulsions. This study aimed to improve the emulsifying properties and interfacial behaviors of CPI through Maillard reaction with citrus pectin (CP). The research findings showed that the covalent linking of CP with CPI caused the unfolding of the molecular structure of CPI, exposing more hydrophobic groups. Consequently, the CPI–CP conjugates exhibited improved emulsifying properties. Emulsions stabilized by CPI–CP conjugates after 12 h of glycosylation demonstrated the smallest droplet sizes (1.73 μm) and the highest negative zeta potentials (−54.7 mV). Glycosylation also improved the storage and environmental stability of these emulsions. Interfacial adsorption kinetics analysis revealed the lower interfacial tension (13.94 mN/m) and faster diffusion rates of the CPI–CP conjugates. Furthermore, interfacial dilatational rheology analysis indicated that the CPI–CP conjugates formed an interfacial layer with a higher viscoelastic modulus (33.214 mN/m) and predominant elastic behavior. The interfacial film of CPI–CP conjugates showed excellent resistance to amplitude and frequency variations, enhancing emulsion stability. Thus, this study demonstrates that moderate glycosylation enhances interfacial performances and improves emulsion stability of CPI, providing new insights into the mechanisms by which CPI stabilizes emulsions.