Comparative study of Ganoderma lucidum hydrocolloids from fruiting bodies and liquid fermentation: Structural characterization and different interactions with gluten networks

Hydrocolloids are widely utilized in the food industry as functional additives to enhance product physical quality, such as improving dough handling, strengthening gluten networks, retaining moisture, and enhancing texture in bread and other cereal-based products. This study assessed the structural and functional properties of Ganoderma lucidum polysaccharides (GLPs, extracted from fruiting bodies) and proteoglycans (GLPg, obtained via liquid fermentation), focusing on their different hydrophobicity drives interactions in gluten networks during formation. Due to the presence of peptide components, GLPg exhibited significantly higher surface hydrophobicity than GLPs, as confirmed by Fourier transform infrared spectroscopy and circular dichroism. This difference in hydrophobicity played a crucial role in modulating their interactions with gluten proteins. The incorporation of GLPs or GLPg into gluten dough (termed GSG and GPG, respectively) increased α-helix and β-sheet content, leading to a smoother surface and more stable, organized gluten structure. The higher surface hydrophobicity in GLPg resulted in fewer hydrogen bonds in gluten. Low-Field NMR revealed that GLPg promoted uniform water distribution in GPG by increasing half-bound water content and shortening relaxation times. By leveraging the distinct structural properties of natural Ganoderma lucidum polysaccharides and proteoglycans, this research gives a comparison of these two natural hydrocolloids and finds GLPg with higher surface hydrophobicity optimizes gluten structure with a stable and stronger network. Our findings offer mechanistic insights into the interactions between fungal hydrocolloids and gluten, providing a scientific foundation for utilizing natural Ganoderma lucidum for innovative functional wheat products.