Tailoring Garlic Bioactive Profiles Through Green Extraction: Comparative Optimization of Microwave- and Ultrasound-Assisted Technologies

Garlic (Allium sativum L.) contains a wide range of bioactive compounds, including phenolic compounds, flavonoids, and organosulfur compounds. Efficient recovery of phenolic and organosulfur compounds from garlic requires extraction technologies capable of selectively preserving chemically distinct bioactive constituents. This study comparatively optimized microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) to elucidate their selectivity toward different classes of garlic bioactive compounds using response surface methodology (RSM) based on a central composite design. The effects of various extraction parameters on total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH, FRAP, and ABTS), and allicin content were investigated. Model performance varied by response: several equations supported prediction within the studied ranges, whereas the MAE TFC and UAE DPPH and ABTS models showed limited predictive ability and significant lack of fit despite the high predicted R2. At the selected conditions, the measured MAE extract contained 58.29 mg allicin/100 g DW after 7 min, whereas the measured UAE extract had TPC and TFC values of 358.7 g GAE/100 g DW and 117.8 g CE/100 g DW, respectively. These observations indicate that the selected conditions produced different bioactive profiles, but do not establish a statistically robust optimum for every response included in the desirability calculation.