Optimization of ultrasound-assisted extraction of polysaccharides from perilla seed meal by response surface methodology: Characterization and in vitro antioxidant activities.

In this study, response surface methodology was employed to optimize the ultrasound-assisted extraction (UAE) process of perilla seed meal polysaccharides (PSMP). The optimal conditions for UAE of PSMP were: liquid-solid ratio of 26.00 mL/g, ultrasonic temperature of 43.00 °C, ultrasonic time of 52.00 min, and ultrasonic power of 229.00 W, the optimal conditions lead to an yield of 6.137 ± 0.062%. The structural characteristics of molecular weight, compositional monosaccharides, and glycosidic linkages were determined by size exclusion chromatography with multiangle light scattering, gas chromatography-mass spectrometry, Fourier-transfer infrared spectroscopy, and nuclear magnetic resonance detections. Scanning electron microscopy analysis showed that many holes were formed on the surface of PSM after UAE. The antioxidant activities of PSMP were investigated using various assays in vitro. The results suggested that PSMP is potential natural resource of antioxidants for medicine and functional foods. PRACTICAL APPLICATION: The selection of raw material perilla seed meal is conducive to the comprehensive utilization of edible resources. With consumer demands for newly developed foods with natural, wholesome ingredients are increasing nowadays. This study provides effective reference for in-depth research on other medicine-food dual-use resources. Ultrasound-assisted extraction (UAE) is a promising alternative method for hot water reflux extraction (HWRE) of polysaccharides for advantages of high efficiency and energy saving. In this work, the UAE process optimized by response surface methodology is more suitable for industrial application that can effectively decrease total cost of production by reducing the extraction temperature, shortening extraction time, and increasing raw material utilization.