Enhancing the Physicochemical Properties, Bioactivity, and Functional Applications of Fresh Jujube Juice Using Media Milling

This study systematically evaluated the effects of media milling on the physicochemical properties, bioactive compound content, and functional applications of fresh jujube (<i>Ziziphus jujuba</i> Mill.) juice. Optimization experiments identified ideal conditions for nanoparticle production, including 5% solid content and a 180 min milling duration, resulting in significantly reduced particle sizes-volume-weighted average diameter (from 229.0 ± 1.0 to 25.0 ± 0.2 μm) and number-weighted average diameter (from 7.2 ± 0.0 to 0.1 ± 0.0 μm)-and improved dispersion stability. Media milling enhanced key physicochemical properties such as zeta potential, viscosity, and suspension stability, while also modifying color and pH. The process notably increased the content of bioactive compounds, including total flavonoids (from 2.9 ± 0.1 to 3.8 ± 0.0 mg catechin equivalent (CE)/g dry weight (DW)) and triterpenoids (from 15.4 ± 1.2 to 28.0 ± 4.9 mg oleanolic acid equivalent (OAE)/g DW). The antioxidant activity before and after media milling, assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, remained comparable. Fermentation with <i>Lactiplantibacillus plantarum</i> demonstrated that both blended and media-milled jujube juice can serve as effective substrates for substrate utilization and lactic acid production. Anti-inflammatory assays using RAW 264.7 macrophages revealed reduced nitric oxide production and lower levels of pro-inflammatory cytokines such as IL-1β, showcasing the juice's potential to modulate inflammation. In a dextran sodium sulfate (DSS)-induced colitis mouse model, media-milled jujube juice demonstrated safety, though it did not show significant protective effects. These findings position media-milled jujube juice as a promising functional food ingredient with potential applications in health promotion and disease management.