Optimization of Ultrasound‐Assisted Extraction and Metabolomic Profiling of a Loquat Leaf–Mulberry Leaf Solid Beverage

Plant‐based solid beverages are attracting increasing interest owing to their health benefits and lower environmental impact. Loquat leaf ( Eriobotrya japonica ) and mulberry leaf ( Morus alba L.) are traditional edible‐medicinal materials rich in bioactive compounds; however, systematic investigations of their combined extraction and process optimization for solid beverage production remain limited. In this study, a loquat–mulberry leaf solid beverage was developed using ultrasound‐assisted extraction (UAE) followed by spray drying. Extraction parameters were optimized through single‐factor experiments and response surface methodology (RSM) with a Box–Behnken design. Untargeted metabolomic profiling of the Yuan Liao (YL), the You Hua Qian (YHQ) beverage, and the You Hua Hou (YHH) beverage was conducted using liquid chromatography–mass spectrometry (LC‐MS) and gas chromatography–mass spectrometry (GC‐MS). The optimal conditions were determined as a loquat leaf to mulberry leaf mass ratio of 30:70 (g/g), a solid‐to‐liquid ratio of 1:25 (g/mL), an ethanol volume fraction of 55%, and an ultrasonication time of 1.8 h, yielding a maximum powder yield of 35.45%. The optimized YHH beverage exhibited higher total polyphenol content (14.3 ± 0.36 mg GAE/g), total flavonoid content (27.8 ± 0.4 mg RE/g), and DPPH radical scavenging activity (178.6 ± 3.9  μ mol TE/g) compared with YHQ. Metabolomic analysis identified 2267 metabolites across all samples. Comparative analysis revealed 90 differential metabolites between YHH and YL, of which 58 were significantly upregulated and 32 downregulated. In contrast, only six differential metabolites distinguished YHH from YHQ, indicating focused changes in key quality‐related compounds. The optimized process improved powder yield and favorably modulated the metabolite profile by increasing beneficial constituents and reducing undesirable ones. This integrated strategy provides a scientific basis and a practical route for the industrial production of high‐quality functional plant‐based solid beverages.