OBJECTIVE Notoginseng Radix et Rhizoma residues were used as raw material to compare the difference in the impact of different probiotics and composite probiotic on various indicator components through probiotic fermentation, aiming to explore the optimal fermentation process.
METHODS The fermentation process was optimized using single factor and Box-Behnken response surface methodology, and the antioxidant capacity of the fermentation product was assessed through in vitro antioxidant experiments.
RESULTS The results showed the optimum fermentation processes were 48 h of aerobic fermentation, 36 h of anaerobic fermentation, ratio of 2 ∶ 3 ∶ 1 for Streptococcus thermophilus, Bifidobacterium bifidum and Lactobacillus acidophilus, solid-liquid ratio of 0.14 g·mL-1, inoculation quantity 5%, fermentation temperature 33 ℃. Under the optimal fermentation conditions, the content of neutral polysaccharide, acidic polysaccharide, and total flavonoid in Notoginseng Radix et Rhizoma residue increased by 105.64%, 96.98% and 123.83%, respectively, which were high than those single-strain fermentation. The IC50 values of scavenging DPPH and ABTS free radicals in the fermentation products were 1.774 mg·mL-1 and 3.065 mg·mL-1, respectively, and the power of reducing Fe3+ was 0.138 mmol FeSO4 g-1. The antioxidant capacity was significantly enhanced compared to the unfermented residues.
CONCLUSION The optimum fermentation process can significantly elevate the content of indicator components in Notoginseng Radix et Rhizoma residues and enhance its antioxidant capacity. Compared to single-strain fermentation, the content of various indicator components is significantly increased, showing no apparent antagonistic effect among the probiotics mentioned above. The study provides scientific evidence and data support for the resource utilization of Notoginseng Radix et Rhizoma residues.
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