Glycosylated Hazelnut Protein as Egg White Alternatives in Nougat Foams: Rheology, Texture, and Microstructure

ABSTRACT This study examined Maillard‐type glycosylated hazelnut protein conjugates as plant‐based alternatives to egg white powder for producing aerated nougat foams. Hazelnut protein isolate (HPI) was conjugated with gum arabic (HPI–GA) or sodium alginate (HPI–SA) under optimized wet‐heating conditions and used to replace egg white powder at 25, 50, 75, and 100% of the control level. Foam performance was assessed by macroscopic appearance and apparent density, steady‐shear flow behavior (power‐law modeling), frequency‐dependent viscoelasticity (G′/G″), texture (spreadability and back extrusion), optical microstructure, and ATR–FTIR. Replacing egg white with native HPI weakened foam structure, yielding higher density, lower viscosity/consistency, and reduced mechanical resistance. In contrast, both conjugates improved foam structuring and deformation resistance, with HPI–SA providing the most pronounced reinforcement, particularly at 25%–50% replacement, where foam properties approached those of the egg white control while maintaining stable bubble dispersion. FTIR features supported the contribution of polysaccharide moieties and stronger hydration‐related interactions in conjugate systems. The findings indicate that glycosylated hazelnut proteins, especially HPI–SA, are promising functional substitutes for egg white in nougat foam formation.