Probiotic goat milk tablets: Formulation optimization and stability evaluation

In this study, a D-optimal mixture design was adopted to evaluate the effect of different excipient combinations of xylitol, erythritol, mannitol, sodium alginate, and microcrystalline cellulose on the quality of probiotic goat milk tablets. Four indicators, namely, viable cell counts, friability, hardness, and sensory evaluation, were used to determine the optimal formulation with xylitol of 9.00%, erythritol of 2.85%, mannitol of 3.00%, microcrystalline cellulose of 0.15%, goat milk powder of 84.90%, and mixed bacteria powder of 0.10%, which can well protect probiotics. In addition, the viability of the probiotics was measured during the storage and in the gastrointestinal tract. The storage stability test showed that the viable counts of probiotics goat milk tablets could still remain at 106 CFU/g after storage at room temperature (25 °C) for 210 days. The simulation experiment in vitro verified that probiotics can tolerate gastrointestinal fluids, reach the intestine smoothly under the protection of the goat milk tablet formula, and exert its probiotic effect. The research demonstrates that the optimal mixture design is reliable and the tablets exhibit high viable counts, have good sensory characteristics, and offer ideal stability, which provides a basis for the development of industrial production of probiotic goat milk tablets.