Extraction And Dyeing Performance Of Plant Pigment

Dioscorea cirrhosa and Walnut green husk are rich in plant pigments,and have pharmacological activity.Pigments extracted from these two plants used as natural dye,not only could achieve dyeing effect,but also could protect hair with their active pharmaceutical ingredients.The purpose of the thesis is to extract pigments from Dioscorea cirrhosa and Walnut green husk,and then to develop a natural black hair dye.The following research work had been carried out:Response surface methodology(RSM)was employed to optimize the ultrasonic-assisted extraction of Dioscorea cirrhosa pigment and microwave-assisted extraction of Walnut green husk pigment.The optimal extraction conditions of Dioscorea cirrhosa pigment were: particle size of 300 ?m,an acetone volume fraction of 74%,solid-liquid ratio of 1:10,temperature of 54 ?C,a time of 31 min,and power of 240 W.The highest extracted yield was 32.27% under these conditions.The optimal extraction conditions of Walnut green husk pigment were: an ethanol volume fraction of 74%,solid-liquid ratio of 1:20,temperature of 61 ?C,power of 612 W,and a time of 10 min.The highest extracted yield was 20.36 mg/g under these conditions.The FT-IR and MALDI-TOF MS were used to determin the structure of Dioscorea Cirrhosa pigment,the main component was condensed tannins with catechol as structural monomers.The effects of pH,temperature,light,metal ions,reductants and oxidants on the stability of Dioscorea Cirrhosa pigment were investigated.The results show that Dioscorea Cirrhosa pigment should be stored at a pH between 3 and 9,below 80 ?C and avoid long time illumination.Metal ions such as Fe2+,Fe3+,and Ti4+ could destabilize Dioscorea Cirrhosa pigment,while K+,Al3+,Ca2+,Cu2+,Mg2+,and Zn2+ had little effect on its stability.Moreover,Dioscorea Cirrhosa pigment showed good anti-reduction and poor anti-oxidization properties.The hair dye with two formulation was developed,by using Dioscorea Cirrhosa pigment,Walnut green husk pigment or mixture in a ratio of 1(25)1 as colorant(I formulation),and Fe2+ as mordant(II formulation).This prepared hair dye could dye white hair into maroon or black,and less damage to hair.