Innovative Fermented Beverages Based on Bread Waste—Fermentation Parameters and Antibacterial Properties.

Featured Application: In response to the contemporary and future challenges for the food production sector in achieving sustainable development goals, this work presents an innovative solution for the management of problematic food waste, such as bakery waste. Prepared beverages based on unused wheat–rye bread fermented using lactic acid bacteria, may be a good starting point for the further development of an innovative, functional food product. Moreover, fermented drinks based on waste from the bakery industry are consistent with the assumptions of sustainable production, and the results obtained in this work may provide interesting information for the circular economy and waste management development. Faced with challenges related to environmental degradation and the growing need for sustainable development, the food sector must look for innovative and ecological production solutions. One of the increasingly popular directions is the zero-waste approach, which limits waste generation and enables its reuse. This research aimed to evaluate selected quality indicators of the lactic acid fermentation process of beverages based on waste from the bakery industry (wheat–rye bread) to determine the optimal fermentation conditions using two strains of lactic acid bacteria: Lacticasibacillus paracasei and Lactiplantibacillus plantarum. Preliminary process optimization was carried out, taking into account the beverage composition, fermentation time, and starting culture. The process evaluation and the selection of the optimal variant were based on the microbiological quality, pH value, and antimicrobial activity of fermented beverages. The results showed that the bread waste may constitute a base for obtaining fermented beverages as evidenced by the high number of lactic acid bacteria, above 10⁸ CFU/mL, and low pH values (≤3.5) after the appropriate incubation time. Fermented beverages exhibited antibacterial properties against tested indicator microorganisms, which confirmed their functional properties. The analysis of the obtained results and the adopted assumptions enabled the selection of the most optimal variant—the beverage with ground flaxseed, fermented by L. paracasei for 24 h. The conducted research indicates great potential for lactic acid fermentation in the management of bakery waste to create innovative, sustainable food products with probiotic potential. [ABSTRACT FROM AUTHOR]