Homologous vs. heterologous proteins in glutinous rice starch: hydrophobic interactions underpin the homologous advantage.

Research on glutinous rice starch (GRS) in combination with proteins remains limited, particularly regarding comparisons between homologous and heterologous proteins. This study aimed to elucidate the functional advantages of homologous glutinous rice protein (GRP) over heterologous rice protein isolate (RPI) in the GRS system and the underlying mechanisms. We compared the GRP-GRS and RPI-GRS systems across multiple scales. GRP, by virtue of its conformational advantages, integrated into the starch network via hydrophobic interactions, enhancing gel strength, hardness, and shear resistance. GRP maintained network integrity at 24% addition level and achieved optimal anti-digestive performance at 3% addition. In contrast, RPI, with its rigid, disulfide-locked conformation, relied on weaker hydrogen bonds, causing network collapse at 24% addition. This study elucidates the homologous advantage mechanism in glutinous rice starch and proposes a formulation design strategy based on conformational flexibility, hydrophobic compatibility, and varietal homology.