Bread wastage is a growing concern in many developed countries. This research aimed to explore the biovalorization of market surplus bread for the development of probiotic-fermented beverages in a zero-waste approach. Bread slurries with different initial total solid contents were inoculated with probiotics Lacticaseibacillus rhamnosus GG (LGG) and Saccharomyces cerevisiae CNCM I-3856, alone and in combination. Our results showed that, of all percentages tested, 5% (w/w, dry weight) initial total solid content resulted in better growth of the probiotics and higher cell counts, while the texture of bread slurries with concentrations higher than 5.0% was too thick and viscous for bread beverage developments. In addition, the development of probiotic-fermented bread beverages was feasible on various types of bread. Furthermore, food additives (sweetener and stabilizer) did not affect the growth of LGG and S. cerevisiae CNCM I-3856 in both mono- and co-culture fermentation. During shelf life measurement, co-inoculation of LGG with S. cerevisiae CNCM I-3856 significantly improved the survival of LGG compared to the mono-culture at 5 and 30 °C, demonstrating the protective effects provided by the yeast. Our study suggests the potential of using market surplus bread as raw materials to deliver live probiotics with sufficient cell counts.
Keywords: Lacticaseibacillus rhamnosus; Saccharomyces cerevisiae; biovalorization; bread; functional beverages; probiotics.