Application of Steam Explosion Technology in Plant Polysaccharides: From Efficient Extraction to Functional Enhancement

Plant polysaccharides are natural polymers composed of aldoses or ketoses. Numerous studies have demonstrated that they possess a wide range of biological functions. Meanwhile, steam explosion is a green, environmentally friendly, and highly efficient pretreatment technology, which can be used to treat raw materials under high-temperature and high-pressure conditions (typically 0.2–2.0 MPa) for a short time (20 s–5 min), followed by instantaneous pressure release, creating an explosive effect. In recent years, steam explosion technology has gained growing attention in the field of plant polysaccharide extraction. By disrupting the cell wall structure and breaking the linkages between cellulose, hemicellulose, and lignin, it reduces the constraints of internal tissues on bioactive components such as polysaccharides, significantly promoting the release and dissolution of water-soluble and low-molecular-mass polysaccharides, consequently enhancing the extraction efficiency of polysaccharides as well as the availability and functional properties of bioactive substances. This technology offers advantages including time-saving, high efficiency, environmental friendliness, and wide applicability. This review offers a systematic overview of the plant sources from which polysaccharides have been successfully obtained using steam explosion technology. It also examines recent progress in the application of this technology, focusing specifically on its effects on the extraction yield, structural characteristics, and composition of polysaccharides. In addition, the impact of steam explosion on polysaccharide bioactivities including antioxidant, hypoglycemic, hypolipidemic, and gut microbiota-modulating activities is summarized in detail. In conclusion, this review may provide a scientific basis and reference for further development and utilization of steam explosion in polysaccharide extraction.