Enhancing the stability of zein pickering foams via hydrophilic reassembly with sugar alcohols and glycosides: A structural and molecular investigation

Abstract

Sucralose (Suc), maltitol (Mal), mannitol (Man), and stevioside (Ste) — a group of alcohol-soluble sugar derivatives with different contents and molecular configurations of hydrophilic groups — were complexed with deaminated zein to significantly enhance the stability of zein-based Pickering foams and develop new composite coacervates to replace animal protein-based foams. Compared with Suc, Mal, and Man, Ste induced better hydrophilic reassembly in zein by forming stronger van der Waals forces and hydrogen bonds, leading to optimum foamability (+160.66%) and foam stability (+17.11%). Moreover, it increased the solubility (+0.07 mg/mL) and decreased the surface hydrophobicity index (−24.88) of zein. These enhancements could primarily be attributed to alterations in the aggregation conformation and hydrophobic interactions within Ste/ZN. Subsequently, SEM and CLSM confirmed that due to the amphiphilic structure of Ste, dispersed zein micelles could aggregate into complex stacking structures. The increase in random coils (+2.48%) and β-sheets (+2.93%) indicated the enhanced flexibility of the zein chain, thereby facilitating zein adsorption and unfolding at the air-water interface. Moreover, molecular simulation demonstrated that an average of 3.1 hydrogen bonds were formed between zein and Ste, and the average binding free energy was −14.20 kcal/mol. These findings provide novel evidence and theoretical guidance for the development of highly stable plant protein-based food foams. The enhancement of Pickering foam stability holds significant implications for the storage and development of high-performance food foams.