Combined use of Trametes versicolor extract and sourdough fermentation to extend the microbiological shelf-life of baked goods

Fungal spoilage is the main responsible for the short shelf-life of baked goods. Indeed, many chemical preservatives (e.g., calcium propionate and ethanol) are often included in their formulation leading to consumer dissatisfaction. Here, an in-vitro and in-situ integrated approach was used to investigate the potential antifungal activity of the extract obtained from Trametes versicolor as biological preservative. An intense inhibition towards most of the Aspergillus and Penicillium species and a broad spectrum of activity on typical spoilage fungi of the bakery products, as well as high thermal stability and intense activity at pH 4.00 characterized the Trametes extract. The antifungal potential of the extract has been exploited in sour bread made with organic acids (chemical) or type II-sourdough (biological). Compared to baker's yeast bread produced as control (pH 5.6), the acidified samples were characterized by a longer mold-free shelf-life, with indicator mycelia that became visible after 6-9 days of storage at room temperature. Sourdough was effective to counteract the negative effect of the extract supplementation on the leavening performances, textural and sensory features of the bread samples.