Physicochemical and viability characteristics of Streptococcus salivarius ATCC9222 orally dissolving strips developed via ultrasound-assisted fermentation

• Orally dissolving strips (ODS) developed as a novel carrier for probiotic delivery. • Ultrasound improved ODS strength, flexibility, and stability. • Fourier-transform infrared showed enhanced protein breakdown and interactions. • Ultrasound ODS had higher probiotic survival before and after saliva. This study examined orally dissolving strips (ODS) incorporating soymilk fermented by ultrasound-treated Streptococcus salivarius ATCC 9222. Ultrasound enhanced protein structural modifications, which translated into improved ODS performance with stronger mechanical strength by 9.0 % and 10.5 % improvement in tensile strength and elongation at break, greater moisture resistance with moisture content reduced by 8.1 % (13.73±0.34 %, p < 0.01) and moisture uptake decreased by 21.5 % at 75 % RH and 9.8 % at 84 % RH, more stable disintegration behavior and more neutral color tones compared with conventional fermentation. In addition, probiotic viability was better preserved during strip incorporation (6.09 ± 0.05 Log10 CFU/mL, p < 0.05) and after simulated saliva exposure (6.39 ± 0.01 Log10 CFU/mL, p < 0.05), indicating superior functional stability. By combining ultrasound processing with probiotic fermentation, this work provides a novel approach to developing plant-based ODS as delivery systems. The findings highlight ultrasound-assisted ODS as promising platform for functional food and nutraceutical applications.