Application of Taguchi Method to Optimize Deep Eutectic Solvent-Based Ultrasound-Assisted Extraction of Polysaccharides from Maca and Its Biological Activity

Deep eutectic solvent (DES) was used for the ultrasound-assisted extraction (UAE) of polysaccharides from maca. Extraction parameters affecting the extraction yield were experimentally identified, and their significance was further investigated using the Taguchi method. DES prepared from choline chloride and urea afforded the highest yield (20.03%) and was chosen as the solvent for UAE. Analysis through signal-to-noise ratios and ANOVA demonstrated that ultrasonic power was the most critical factor affecting the extraction process with the highest delta value of 10.13 and a contribution rate of 48.13% (p < 0.001). The optimal extraction parameters that obtained the highest yield were identified as follows: a water content of 30% for DES, an ultrasonic power setting of 300 W, and an extraction time of 20 min. The extraction yield (26.28%) of maca polysaccharides (MPs) obtained using optimal extraction parameters was more than twice that of MPs obtained by hot-water extraction and UAE with water. Moreover, MPs obtained through DES-based extraction exhibited various biological functions such as inhibiting pancreatic α-amylase and α-glucosidase activities, delaying absorption of glucose and bile acid, and stimulating the probiotic. Therefore, DES can be used to extract polysaccharides from maca with biological action as a highly efficient and non-polluting alternative solvent.