Microwave-assisted enzymatic extraction brings a notably high yield of polysaccharides from mountain Zizania latifolia.

Abstract

Mountain Zizania latifolia is produced at scale in China, and the edible swollen culm is exported to many countries, but little attention has been paid to its functional components. In this work, microwave-assisted enzymatic extraction (MAEE) is used for the first time to extract polysaccharides from mountain Z. latifolia swollen culm (PMZL). MAEE conditions optimized by Box-Behnken design-response surface methodology were as follows: 2.4% cellulase, microwaving for 6.0min at 607W, with a liquid-to-solid ratio of 63:1mlg-1 . Under these conditions, a notably high yield of 60.43%±1.12% for PMZL was achieved, which was significantly higher (p<0.01) than from plain-grown varieties. PMZL are naturally occurring sulfated polysaccharide-protein complexes containing 8.46%±0.18% proteins and 7.86%±0.73% sulfates. PMZL comprises mannose, glucosamine, rhamnose, glucose, galactose, and arabinose at molar ratios of 3.80:2.68:1.00:17.41:5.12:2.91, with a weight-average molecular weight of 1569,219Da and a number-average molecular weight of 364,088Da. The surface morphology of PMZL is composed of tightly packed oval particles, and this kind of promising polysaccharides preferentially scavenges reactive nitrogen species. PRACTICAL APPLICATION: Due to global warming, the land available for planting vegetables is likely to expand to higher areas, so greater attention should now be paid to mountain-grown vegetables. This study provides an efficient way to obtain novel polysaccharides from mountain Zizania latifolia using microwave-assisted enzymatic extraction with a remarkably high yield of 60.4%. This promising source of natural carbohydrates has potential uses in pharmaceutical, nutraceutical, functional foods, cosmetics, and functional materials industries.