Gum arabic-mediated modification of hazelnut protein via Maillard conjugation: Functional enhancement with minimal 5-hydroxymethylfurfural formation

Abstract

Plant-based protein isolates, such as hazelnut protein isolate (HPI), are characterized by low solubility and limited emulsifying properties, which restrict their utilization in food formulations. This study aimed to enhance the techno-functional properties of HPI through Maillard-type conjugation with gum arabic (GA) under controlled wet thermal conditions. Temperature, heating time, and protein ratio were evaluated as independent variables. Optimum conditions (70 degrees C, 6 h, 45% protein content) were identified by maximizing the degree of glycation, solubility, and emulsion activity/stability while minimizing 5-hydroxymethylfurfural (HMF) formation. Optimized GA-HPI conjugates exhibited markedly improved solubility (83.82%), emulsion activity (27.85 m2/g protein), and stability (134.46%) with relatively low HMF levels. Structural analyses (FTIR, sulfhydryl, zeta potential, surface hydrophobicity) confirmed protein unfolding, covalent attachment of saccharide moieties, and exposure of reactive groups, whereas rheological and SEM analyses demonstrated reduced viscosity, enhanced thermal stability, and altered morphology. Overall, GA conjugation significantly improved the structural and functional attributes of HPI, highlighting its potential as a clean-label protein-polysaccharide conjugate for use in emulsified foods, protein-enriched beverages, and dairy alternatives.