Surplus bread was hydrolyzed with enzymes and fermented by LAB.
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LAB fermentation increased the antifungal activity of the hydrolyzed bread.
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Nine peptides with antifungal properties were identified in the active hydrolysate.
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Bread with the active hydrolysate had a shelf-life of 10 days.
Abstract
Bread is one of the most consumed food products in the world and one of the most discarded, due to its intrinsic short shelf-life and susceptibility to mold spoilage. Additionally, bread waste is generated during production and distribution, leading to the disposal of bread otherwise still fit for consumption. To avoid generating huge amount of bread waste, strategies to enable its reutilization should be sought. In this study, surplus bread, still suitable for consumption, was bioprocessed with enzymes and fermented by selected lactic acid bacteria generating an ingredient with antifungal properties. Bread hydrolysate fermented by Lactobacillus brevis AM7 showed broad inhibitory spectrum against the fungal species tested and antifungal activity ranging from 20 to 70%. Nine antifungal peptides were identified via Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra (nano-LC-ESI-MS/MS), having 10–17 amino acid residues and mass ranging from 1083.6 to 1980.7 Da, all of them encrypted in wheat proteins sequences. Bread hydrolysate fermented by Lb. brevis AM7, non-fermented bread hydrolysate and a slurry consisting of water-bread mixture were used as ingredients in bread making and compared to regular wheat bread. Breads containing the fermented hydrolysate (18 and 22% of the dough weight) showed the longest mold-free shelf-life compared to the other breads, lasting up to 10 days before mold appearance. Additionally, the fermented hydrolysate was the least detrimental on bread quality, emphasizing the positive impact and potential of the studied biotechnology.
