Optimization of decolorization and dyeing process of leaves of Magnolia officinalls

Magnolia officinalis is the raw material of traditional Chinese medicine, its leaves are widely used as food packaging material. In this study, effects of ethanol (decolourant)and sodium copper chlorophyllin (coloring agent)on Magnolia officinalls leaves preserved in 20% NaCl condition by single factor and orthogonal design methods were investigated. The result showed that the optimum conditions were decolorization ethanol concentration of 80%, solid liquid ratio of 1:50 g/mL, temperature of 70℃ and time for 3 h, the color of Magnolia officinalis leaves was changed to tea yellow. Also, the best dyeing combinations were sodium copper chlorophyllin concentration of 4 g/L, solid liquid ratio of 1:5 g/mL, temperature of 95℃ and time of 40 min.Under these conditions, the color of leaves was retied to bright green. This improved process achieved satisfactory results in leaves products of Magnolia officinalis.