Optimization of Supercritical CO₂ Operative Parameters to Simultaneously Increase the Extraction Yield of Oil and Pentacyclic Triterpenes from Artichoke Leaves and Stalks by Response Surface Methodology and Ridge Analysis

Abstract

Supercritical carbon dioxide (SC‐CO 2 ) extraction is carried out to simultaneously increase yield of extracted oil and the content of pentacyclic triterpenes from residual parts of globe artichoke. Box‐Behnken design is used to design a set of comprehensive experiments. Single and interactive effects of four processing variables (pressure, temperature, time, and particle size) are investigated by response surface methodology (RSM), which is also used to establish regression model according to the synthesis score of extracted oil and pentacyclic triterpenes (PTs). On the other hand, the combination of SC‐CO 2 factors is optimized by ridge analysis. As a result, the optimal combination is obtained at 22.27 MPa, 41.33 °C, particle size of 53.66 mesh within 2 h. Furthermore, the oil components extracted from SC‐CO 2 and Soxhlet extraction (SE) are analyzed using GC‐MS. In contrast with SE, SC‐CO 2 is more effective to increase the content of PTs in extracted oil of globe artichoke. Practical Applications : Industrial processing of globe artichoke can cause 80–85% waste of total plant biomass, which mainly consists of the inedible parts. However, the by‐products of globe artichoke contain many kinds of nutritional compounds, such as sesterpenes and triterpenes. The application of SC‐CO 2 can extract these compounds safely and effectively. With optimization of SC‐CO 2 , sustainability of processing of globe artichoke can be maintained economically. A processing method of supercritical carbon dioxide (SC‐CO 2 ) extraction is optimized to increase the yield of extracted oil and the content of pentacyclic triterpenes (PTs) simultaneously from globe artichoke. Afterward, the pentacyclic triterpenes in the extracted oil are analyzed by GC‐MS and six types of PTs in globe artichoke are identified. Additionally, the influence of SC‐CO 2 extraction is analyzed using the principal component analysis method. Meanwhile, the interactions of two processing factors on the yield of extracted oil are analyzed.