Development of a fermented plant-based beverage from discarded bread flour

Abstract

This work aimed to reuse bread flour from discarded bread as a substrate for the growth of probiotic lactic acid bacteria (LAB) and Bifidobacterium. Commercial starters were used to ferment beverages based on bread waste flour and water, with and without enzymes (α-amylase and β-glucoamylase) and with and without a desalting treatment. All the fermentations were carried out at 38 °C during 24 h. Microbial counts, pH and titratable acidity (TA) were determined at 0, 3, 6, 9 and 24 h and carbohydrates content at 0, 9 and 24 h. The pH, TA and water holding capacity (WHC) were also analysed at 15 and 21 days during the storage of the beverages. Both starters showed good growth during the first 9 h although Nu-trish® BY showed a slight decrease until the end of the fermentation. All the beverages reached pH levels lower than 4.1 after 24 h. Samples treated with enzymes achieved faster a higher acidity and a lower WHC. In general, salted samples showed higher maximum rates of growth (μmax) and maximum rates of pH reduction (Vmax pH red) and acidification (Vmax acid), as well as lower pH and WHC and higher TA, in all the studied analyses.