Prebiotic potential of macerates derived from solid-state fermentation of barley straw by Rhizopus oryzae JCP024: preliminary evaluation

The objective of this research was to obtain a macerate with prebiotic potential from barley straw obtained after fermentation in solid-state. Fermentation process was carried out for 7 weeks at 30 C using sterilized barley straw inoculated with Rhizopus oryzae JCP024. Spores number, changes in pH, and carbohydrates were monitored every 24 h. Deionized water was used to obtain the macerates of the fermented barley straw. The concentration of reducing carbohydrates and the total carbohydrates was determined by using DNS and Dubois technique, respectively. The effectiveness of the macerates as prebiotics was verified through a viability study with L. casei Shirota. Inulin was used as prebiotic control. Reducing carbohydrate content decreased until total carbohydrates increased due to the consumption of carbohydrates by the fungal biomass and hydrolysis of oligosaccharides at the same time. A constant viable count of the probiotic was observed, being comparable to that observed in the control (1 × 108 CFU/mL). With these results, it is demonstrated that the macerates of an agricultural waste obtained during fungal fermentation could be an alternative for obtaining carbon sources for probiotic growth.