Effects of ultra-high-pressure on the quality of polysaccharides from the fresh stems of Dendrobium officinale

Fresh medicine is the use of fresh Chinese herbs after mining. The aim of the present work was to investigate the feasibility of ultra-high-pressure processing in the fresh medicine field. The typical fresh medicine Dendrobium officinale was used as the research material. The effects of pressure level (100 - 500 MPa), processing duration (0.5 - 2.5 min), number of processing cycle (1 - 5), and temperature (20 - 100 degrees C) on the polysaccharide loss (in pressure transmitting medium) and dissolution efficiency (in boiling water) were studied. The results show that all parameters not only caused a dramatic loss of polysaccharides but also significantly increased the dissolution quantity, with the largest loss resulting from the number of repetitive processing cycles, which reached 47.11% after five processing steps. Analysis of the infrared spectroscopy and antioxidant activity results showed that the structure and antioxidant activity of the polysaccharides extracted from the stems processed by the parameters with the maximum value were markedly different, and the antioxidant activity of the polysaccharides extracted from the stems processed five times was the weakest. Ultra-high-pressure processing has good prospects in fresh medicine, while further research on process optimisation is necessary. (C) All Rights Reserved