Improving properties of dough and bread through the synergistic effect of chitosan and fermented whey

Background To improve bread quality and mitigate the potential health risks associated with synthetic preservatives such as sodium dehydroacetate (SD), this study developed a natural preservative system composed of chitosan (CS) and fermented whey (FW) as an alternative. Results A series of bread formulations containing different ratios of CS and FW (0.5% CS + 0% FW, 0% CS + 0.5% FW, 0.5% CS + 0.5% FW, 1% CS + 0% FW, and 0% CS + 1% FW), along with 0% additive and 0.1% SD, were investigated. Among these, the composite of 0.5% CS and 0.5% FW was identified as optimal. Rheological analysis and scanning electron microscopy showed that this composite significantly enhanced dough viscoelasticity and promoted the formation of a stronger gluten network capable of effectively retaining gas. In subsequent bread quality assessments, the CS–FW composite markedly increased specific volume by 12.4% and slowed staling, whereas SD addition reduced specific volume by 27.2% and accelerated the staling process. During 42 days of storage, bread containing the CS–FW composite maintained aerobic plate count below 10 CFU g −1 and exhibited lower hardness and chewiness, higher elasticity, and more stable moisture, resulting in a shelf life extended approximately sixfold compared with the blank group. Conclusion The CS–FW composite matched or exceeded the effectiveness of the synthetic preservative SD through a multi‐targeted mechanism that simultaneously enhanced sensory properties and ensured microbial safety. This work provides a natural, dual‐function approach for extending bread shelf life and improving overall product quality.