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.
Keywords: Sagittaria trifolia tuber polysaccharides; antioxidant potential; characterization; microwave-assisted enzymatic extraction.
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