Abstract:A response surface numerical model was developed to optimize the fermentation conditions of Qu tangerine peel with Lactobacillus plantarum based on total flavonoid content. The quality evaluation of the product encompassed physical and chemical properties，antioxidant activity，and microbial indicators. The findings revealed that the optimal fermentation conditions comprised a bacterial inoculum amount of 23 μL/mL，the fermentation duration of 42 h，a sugar concentration of 16 mg/mL，and a fermentation temperature of 33 ℃. Under these optimized conditions，the total flavonoid content in the fermentation product of Qu tangerine peel reached 17.423 μg/mL. The pH and ethanol content complied with the standards outlined in QB/T 5323—2018 Plant Enzymes. No mold or coliform bacteria were detected in the Qu tangerine peel enzyme solution. The DPPH free radical scavenging rate stood at 65.82%，and the superoxide dismutase activity was measured at 2.55 U/mL.