Abstract:To develop a fermented jujube juice with excellent flavor，Lactobacillus rhamnosus was used to ferment dried Lingwulong jujube. Sensory evaluation and lactic acid content served as assessment criteria. A combination of single-factor experiments and response surface methodology optimized the fermentation process.The physicochemical properties，microbiological indicators，antioxidant activity，and flavor compounds were also investigated. The results indicated that the optimal fermentation conditions for L. rhamnosus fermented jujube juice were as follows：inoculum level of 4.5%，white sugar addition of 4.5%，fermentation temperature of 36 ℃，and fermentation time of 13 h. Under these optimal conditions，the fermented jujube juice exhibited a lactic acid content of 13.62 g/L and a sensory score of 89. Compared to unfermented jujube juice，the fermented jujube juice exhibited increased viable bacterial counts，total phenolic content，and total flavonoid content，while decreased pH，total sugar content，and reducing sugar content. The fermented jujube juice exhibited enhanced scavenging capacities against ABTS+，DPPH，and hydroxyl radicals by 18.96%，18.96%，and 35.56%，respectively. Furthermore，34 volatile compounds were identified in both the unfermented and fermented jujube juices. Compared to the unfermented juice，nine new volatile compounds emerged in the fermented juice，with increased relative levels of esters and ketones，indicating that L. rhamnosus fermentation altered the flavor profile of jujube juice.