Optimization of Extraction Technology and Stability of Black Rice Pigment

In this paper, black rice was used as material to extract black rice pigment by alcohol extraction so as to achieve the goal of making full use of black rice resources. The effects of solid-liquid ratio, ethanol volume fraction, extraction temperature and time on the extraction absorbance of the pigment were investigated. On the basis, the response surtace method was used to optimize the extraction parametres of black rice pigment, the effects of temperature, pH, light, oxidation agent on the stability of the effect of black rice pigment were investigated. The results showed that the optimum conditions for extraction of black rice pigment as follows:Solid-liquid ratio 1:30.5 g/mL, ethanol volume fraction 44%, extraction temperature 90℃, and extraction time 104 min. Black rice pigment was stable under 90℃, under light condition and pH2~6 acid environment, but the presence of oxidant H₂O₂ wouldl affect the stability of black rice pigment. Therefore, black pigment should be carried out under low temperature and acidic conditions, and it could be kept away from light. However, it should avoid contacting with oxidants during storage and transportation.The technology was reasonable and reliable, which would provide a theoretical basis for industrial extraction of black rice pigment.