Aims
The aim of this study was to investigate the effectiveness of bread as substrate for γ‐aminobutyric acid (GABA) biosynthesis, establishing a valorization strategy for surplus bread, repurposing it within the food chain.
Methods and Results
Surplus bread was fermented by lactic acid bacteria (LAB) to produce GABA. Pediococcus pentosaceus F01, Levilactobacillus brevis MRS4, Lactiplantibacillus plantarum H64 and C48 were selected among 33 LAB strains for the ability to synthesize GABA. Four fermentation experiments were set up using surplus bread as such, added of amylolytic and proteolytic enzymes, modifying the pH or mixed with wheat bran. Enzyme‐treated slurries led to the release of glucose (up to 20 mg g−1) and free amino acid, whereas the addition of wheat bran (30% of bread weight) yielded the highest GABA content (circa 800 mg kg−1 of dry weight) and was the most suitable substrate for LAB growth. The selected slurry was ultimately used as an ingredient in bread making causing an increase in free amino acids.
Conclusions
Besides the high GABA concentration (148 mg kg−1 dough), the experimental bread developed in this study was characterized by good nutritional properties, highlighting the efficacy of tailored bioprocessing technologies as means to mitigate food wastage.
Significance and Impact of Study
Our results represent a proof of concept of effective strategies to repurpose food industry side streams.
Bread is an important staple food consumed worldwide. However, bread is also among the major food waste in many countries around the world. Annual global production of bread exceeds 100 million tons and estimated wastage for bakery goods is about 7-10% (Melikoglu & Webb, 2013;Mena et al., 2011), implying a substantial amount of food escaping from human nutrition. During the bakery process, waste is produced from overproduction of bread, excess dough, dusting flour, and from defective products that randomly occur during the production line. Current means to deal with bakery waste involves incineration, utilization as animal feed, or biofuel production, whereas efficient recycling back to food industry is nonexisting. Research has been done to develop strategies for waste bread
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