Waste bread recycling as a baking ingredient by tailored lactic acid fermentation

Area of Science:

• Food Science
• Microbiology
• Sustainable Food Systems

Background:

• Food-grade waste from the baking industry is often used for non-food purposes.
• Sustainable food systems require maximizing food use, including waste streams.

Purpose of the Study:

• To explore the potential of recycling waste wheat bread for fresh bread production.
• To assess the impact of lactic acid bacteria fermentation on waste bread properties for reuse.

Main Methods:

• Waste bread was assessed untreated or after fermentation with lactic acid bacteria producing dextran or β-glucan.
• The effect of waste bread slurry addition on new bread quality (specific volume, softness) was evaluated.
• In situ exopolysaccharide (EPS) production and its impact on bread quality were analyzed.

Main Results:

• Non-treated waste bread decreased new bread quality.
• In situ EPS production (dextran) increased slurry viscosity and provided residual sugars for yeast leavening.
• Fermentation with Weissella confusa A16 produced dextran, improving bread specific volume by 12% and reducing crumb hardness by 37%.

Conclusions:

• Waste bread fermented by W. confusa A16 with dextran production enables safe recycling with minimal quality loss.
• Dextran effectively counteracted the negative effects of recycled bread on bread quality attributes.
• Microbial β-glucan did not yield a positive technological outcome in this study.