## 4 Extraction Methods for Coriander Bioactive Compounds
### Non-Conventional Extraction Methods
#### 4.2.1 Microwave-Assisted Extraction
Similarly, [PERSON], [PERSON] [121] optimized the extraction of TPC and total antioxidant capacity (TAC) from coriander leaves using MAE and RSM, achieving yields of 49.63 mg GAE/g dw for TPC and 5.55 mg GAE/g DW for TAC under optimal conditions, which confirmed the effectiveness of their model. Meanwhile, [PERSON], [PERSON] [122] have also used an effective ionic liquid-based microwave-assisted extraction (IL-MAE) technique to recover the molecule responsible for the radical scavenging activity in coriander foliage, namely, Heneicos-1-ene, followed by its quantification via HPLC. The RSM was applied to determine the optimal levels of six parameters affecting the extraction, such as material/solvent ratio, types of IL, IL concentration, microwave power, temperature, and extraction time, to maximize yield. Using a 0.1 M solution of 1-Butyl-3-methylimidazolium tetrafluoroborate, optimal conditions were achieved at 800 W and 90 \({}^{\circ}\)C over 2 min at a material-to-solvent ratio of 1:10. Under these conditions, a maximum predicted yield of Heneicos-1-ene (412.8 mg/100 g), compared to 408.50 \(\pm\) 1.14 mg/100 g for the experimental value, was obtained. Compared to the conventional method (69.77 \(\pm\) 1.8 mg/100 g), the IL-MAE gave a 5.85 times higher yield. Other studies, however, were conducted with the aim of comparing two extraction processes: hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD). The comparison carried out by [PERSON], [PERSON] [123] is based on the effects of microwave radiation on the amount, quantity, and antimicrobial activity of coriander fruits EOs. The yields of the extraction from HD and MAHD were 0.2% and 0.1%, respectively. The findings showed that monoter, including linalool, geranyl acetate, and \(\gamma\)-terpinene, dominated the two extracted oils, with linalool being the primary constituent of both extracts. Both oils also showed activities against the tested bacterial species. This study concluded that despite the decrease in oil yield and total composition when applying the innovative MAHD method, its use proved to be superior in terms of energy saving and extraction time. Similarly, the comparison led by [PERSON], [PERSON] [124] was based on the results of the chemical composition and TPC as well as the antimicrobial and antioxidant properties of EOs from coriander seeds. The results revealed that no significant difference (\(p>0.05\)) was noticed between the extraction efficiency of the HD (0.31%) and MAHD (0.325%) methods. Nevertheless, they indicated that the MAHD extraction process was a better method for the separation of EOs as it had the advantage that the extraction time was shorter (60 min vs. 240 min). Furthermore, in terms of energy consumption and cost, MAHD was also more economical. The previous paragraphs have examined the effectiveness of MAE compared with conventional extraction methods, and it can be concluded that MAE and MAHD offer significant advantages in terms of speed, energy efficiency, and the yield of bioactive compounds compared with conventional extraction methods. However, challenges remain, particularly in terms of optimizing extraction parameters and standardizing processes to ensure reproducible results. Future research should focus on improving these methods to maximize their industrial potential while minimizing costs and environmental impact.