Quality evaluation method for Chinese medicine based on color grading

Traditional identification method is an effective approach to evaluate the quality for Chinese herbal medicine (CHM). Color is one of the important indicators for quality evaluation due to high correlation with quality. Therefore, a new theory of quality control for CHM based on color grading was discussed in this article. The scientific nature of this theory was illustrated by investigating the relation between CHM color, medicinal properties and active compound contents. The effect of origins, collecting time, processing, and storage on the CHM color was also analyzed. To overcome the drawback of the traditional identification method, the novel objective color evaluation methods such as spectrocolorimeter and machine vision technology were reviewed, including the application, advantages and disadvantages in Chinese medicine field, and the significance of color sense digitalization was illustrated finally.