Optimization of Supercritical CO₂ Extraction and Comparative Analysis of the Quality of Zanthoxylum Oleoresin Prepared by Different Extraction Methods

Using Han Yuan Nan Jiao as raw material, the supercritical CO₂ extraction (SFE) process was optimized, and the differences in physicochemical properties, sensory characteristics, volatile components, and numbing compound contents of Zanthoxylum oleoresin prepared by SFE, ethanol solvent extraction method (SEM), and cold pressing method (CP) were systematically compared. Results showed that the optimal SFE conditions were an extraction pressure of 30.4 MPa, temperature of 38.7 ℃, and time of 1.9 h, achieving a Zanthoxylum oleoresin yield of 12.72%. The SFE product exhibited pure and intense numbing sensation (8.3 points) with mild aromatic notes (rosin and citrus), achieving the highest comprehensive sensory score. A total of 83 volatile components across 5 categories were detected in the Zanthoxylum oleoresin, with limonene, myrcene, linalool, and linalyl acetate being the predominant compounds across all three methods. The total numbing compound content of the SFE sample (597.75 mg/g) was significantly higher than those of SEM (438.60 mg/g) and CP (384.52 mg/g) samples. Among the 10 numbing amides, hydroxyl-α-sanshool, hydroxyl-β-sanshool, and hydroxyl-γ-sanshool were the most abundant. This study provides technical support for the industrial production of high-quality Zanthoxylum oleoresin and confirms the comprehensive advantages of supercritical CO₂ extraction in flavor and functional properties.