Reformulating wheat dough and bread using second cheese whey

Second cheese whey (SCW), a major dairy by-product, was explored as an ingredient for breadmaking to promote its valorisation. For this purpose, non-fermented (NF-SCW) and Propionibacterium freudenreichii-fermented second cheese whey (F-SCW) were incorporated into dough at 50% and 100% water substitution levels, and their effects on dough rheology and bread quality were evaluated. Results showed that SCW incorporation, irrespective of fermentation state, enhanced dough viscoelastic-significantly (p < 0.05) increased storage and loss moduli values-and viscosity parameters in a dose-dependent manner while maintaining fermentative performance comparable to the control dough (100% water). Regarding bread quality, total water substitution with both NF-SCW and F-SCW resulted in a significantly (p < 0.05) reduced specific volume (2.36 and 2.38 mL g(-1), respectively, compared to 2.70 mL g(-1) for the control), significantly (p < 0.05) increased crumb hardness (17.01 and 14.37 N respectively, compared to 10.87 for the control), and coarser crumb structure compared to the control. Conversely, partial substitutions, particularly with F-SCW, mitigated these adverse effects, yielding values for the tested parameters statistically comparable (p > 0.05) to control bread. These findings demonstrate that moderate SCW incorporation in breadmaking represents a sustainable and viable dairy waste valorisation strategy. Furthermore, following fermentation, propionic and acetic acids, two metabolites known for their antimicrobial properties against common bread spoilage organisms, were detected in F-SCW at concentrations of 1.55 and 3.07 g L-1, respectively. This suggests a promising avenue for future investigation of their potential effect on bread shelf life.