Effects of Processing on Structural Properties and Biological Activities of Polysaccharides from Polygonatum spp.: A Review

Rhizomes from Polygonatum spp. have multi-functions of both medicine and foods. Three major species are Polygonatum sibiricum Red., Polygonatum kingianum Coll. et Hemsl and Polygonatum cyrtonema Hua. As the key component, the polysaccharides from Polygonatum spp. have various biological activities. The astringency of fresh rhizomes of Polygonatum spp. can cause throat irritation. Thus, the rhizomes of Polygonatum spp. must be processed before consumption as foods or medicine to reduce toxicity and enhance efficacy. However, both of traditional and modern processing methods lead to significant reduction in polysaccharide content, which also change its structure and biological value. Thus, based on literature research, this article summarizes common processing methods of Polygonatum spp., including steaming, stewing, with wine, and shining. In addition, effects of processing methods on polysaccharide content, its structural properties (including monosaccharide composition, molecular weight, etc.), and its physiological activities (including antioxidant activity, regulation of glucose and lipid metabolism, immune-enhancing activity, anti-fatigue activity, antibacterial activity, etc.) are reviewed. It is meaningful to provide references for efficiently industrial use and accurate control during processing of Polygonatum spp..