The effects of different drying methods on the drying characteristics and quality of Polygonatum odoratum

The effects of five different drying methods,such as microwave vacuum drying, natural drying, microwave drying, vacuum drying and hot air drying,on the dry curve of Polygonatum sibiricum and the contents of polysaccharides,total phenolics, total saponins, 5-carboxymethylfurfural and the polysaccharide antioxidant activity were studied. The polysaccharides, total phenols,total saponins and 5-hydroxymethylfurfural of Polygonatum sibiricum were extracted by ultrasonic-assisted method respectively,and their contents were determined by the corresponding literature methods.At the same time,the antioxidant activity of Polygonatum polysaccharides was detected by FRAP and superoxide anion free radical assay.The results showed that the drying rate of microwave vacuum drying method was the highest and its drying time was the shortest,the contents of polysaccharides,total phenol and total saponins in the dried products of Polygonatum sibiricum were the least, and the furfural production of 5-carboxymethylfurfural was lesser.In addition,the polysaccharide content was(63.59±1.25) mg·g^-1,and the inhibitory rate of 20 mg·mL^-1 polysaccharide solution on superoxide anion radical was 30.01%±1.30%. The microwave vacuum drying method is more suitable for obtaining high-quality dried product of Polygonatum sibiricum.