Microwave‐Assisted Enzymatic Extraction, Partial Characterization, and Antioxidant Potential of Polysaccharides from Sagittaria trifolia Tuber

Sagittaria trifolia tuber is an aquatic vegetable. In this work, microwave‐assisted enzymatic extraction (MEE) was used to extract S. trifolia tuber polysaccharides (STTPs). Optimum conditions were complex enzyme of 2 %, liquid‐to‐solid ratio of 43 : 1 mL g−1, microwave power of 506 W, and time of 8 min, under which STTPs yield was 36.22±0.69 %, higher than those of other methods. STTPs were sulfated polysaccharides with sulfur valence of S6+. STTPs comprised mannose, glucose, galactose, and arabinose at a mole ratio of 3.69 : 19.33 : 6.21 : 1.00, molecular weights of 3606 kDa and 149.6 kDa, particle size of 220 nm, and zeta potential of −5.02 mV. The surface of STTPs was full of bumps and holes, and abundant in O1s and non‐functionalized C1s. STTPs would scavenge reactive oxygen species with advantage. It would provide an efficient MEE method to obtain antioxidant STTPs, also a clue for extracting polysaccharides from starch‐rich crops.