Dialdehyde cellulose-l-lysine Schiff base conjugate synergistically modulates water status, texture, and antibacterial activity of wheat gluten.

To address poor water retention, texture deterioration, and microbial contamination in gluten-based products, a dialdehyde cellulose-l-lysine Schiff base conjugate (DAC-Lys) was synthesized. DAC-Lys-2 (12 h oxidation, 4-6% addition) densified the network with more regularly distributed pores, increased tightly bound water from 6.93% to 8.32% and reduced mobile water from 82.91% to 80.75%, indicating significantly restricted water mobility. Baked gluten containing 6% DAC-Lys-2 exhibited 44.61% lower hardness and 39.13% higher elastic force than unmodified gluten, a "soft yet elastic" texture. DAC-Lys-2 showed antibacterial activity against Escherichia coli (12.42 ± 0.24 mm), Staphylococcus aureus (12.49 ± 0.17 mm), Salmonella (12.26 ± 0.09 mm), and Bacillus cereus (14.36 ± 0.46 mm), with free aldehyde residues (50.03-67.36 μg/g). The mechanism involves Schiff base crosslinking and hydrogen bonding that pre-structure the gluten network and directionally convert mobile water to bound water. DAC-Lys has been demonstrated to be a promising modifier for gluten-based foods, providing synergistic improvements in water retention, texture, and antibacterial functionality.