Effects of Spirulina on Mixing, Rheology, and Structure in Wheat Dough

Spirulina, a nutrient-rich microalga, was incorporated into wheat flour at 0–4% (flour basis) to evaluate its effects on dough mixing, rheology, water distribution, microstructure, and protein aggregation. The water absorption value increased from 56.2% (control) to 58.8–60.4% with Spirulina addition; however, the change was not statistically significant (p > 0.05). At 1–3% addition, development time increased from 2.2 to 2.4–2.7 min and stability from 4.9 to 6.4 min, while 4% addition reduced stability and increased weakening. Rheological measurements showed that G′ and G″ decreased by 23–33%, while tan δ increased from 0.37 to 0.38–0.39, indicating reduced viscoelastic strength. The LF-NMR results showed that A21 exhibited an increasing trend (p > 0.05), accompanied by a prolongation of T22, indicating enhanced water mobility and reduced binding strength. Microscopy showed a more continuous gluten network at 1–3%, whereas discontinuities appeared at 4%. SDS-PAGE indicated increased >60 kDa aggregates at 3% but reduced intensity at 4%. Overall, 1–3% Spirulina, particularly 3%, was associated with improved mixing tolerance and more uniform structural characteristics.