Combined effects of Polygonatum cyrtonema flour and thermal treatment on the structural, rheological, and functional properties of wheat gluten.

Background

Polygonatum cyrtonema flour (PCF) is increasingly incorporated into wheat products for nutritional enrichment. However, its quality effects are inconsistent and concentration-dependent, and the gluten modulation mechanism remains unclear. This study investigates the combined effects of PCF incorporation and thermal treatment on gluten structure and functionality using varying levels of 0 (PCF-0), 75 (PCF-75), 150 (PCF-150), and 300 g kg-1 (PCF-300) of PCF, followed by thermal treatment at 25, 60, and 95 °C.

Results

At 25 °C, PCF-300 increased free sulfhydryl (free - SH) by 94.7% and decreased surface hydrophobicity (H0) and fluorescence, disrupting covalent cross-linking, promoting hydrophobic interactions, and loosening secondary structure (branching -54.8%, strand width +113.3%), yielding a sparse network with reduced viscoelasticity, water-holding capacity (WHC), and emulsifying activity index (EAI). At 95 °C, heating reversed these effects: PCF-75 and PCF-150 promoted tight cross-linking, enhancing WHC (2.0 g g-1, +25.4%), EAI and emulsion stability index (+20.6-49.9%); PCF-300 preserved free - SH (H0 decline 10.8%) via steric hindrance, giving a flexible network. At 60 °C, PCF-150 and PCF-300 induced transient unfolding (fluorescence +21.7-29.4%) with local β-sheet formation, loosening the network. Oil-holding capacity decreased with PCF and heating (maximum -45.3% at PCF-300/25 °C).

Conclusion

These antagonistic-to-synergistic effects enable targeted design: PCF-75 and PCF-150 at 95 °C enhance water retention and emulsification for clean-label baked goods; high-PCF heating reduces oil absorption for low-fat products; the 60 °C window offers a kinetic route for hydrophobic bioactive delivery, providing a mechanistic basis for rational PCF incorporation into healthier wheat foods. © 2026 Society of Chemical Industry.