OBJECTIVE To quantitatively characterize the color and odor of Gansu ginger and its processed products(dried ginger and baked ginger), and determine their volatile compounds by GC-MS.

METHODS  Colorimeter, PEN3 electronic nose system and GC-MS were used to analyze the colorimetry and odor of Gansu ginger, dried ginger and baked ginger in Gansu province by principal component analysis, loadings analysis, discriminant analysis, partial least square analysis and Pearson correlation analysis, and the obtained characteristic data were processed and analyzed.

RESULTS  Based on the discriminant analysis of color value L*, a*, b*, the color and appearance of ginger, dried ginger and baked ginger were obviously distinguished, and the whole showed a trend of darkening, red and blue. In the analysis of odor response, sulfur compounds had the highest response value, followed by nitrogen and oxygen compounds. GC-MS spectrometry identified 31 volatile compounds from ginger, 22 volatile compounds from dried ginger, and 20 volatile compounds from baked ginger. Pearson correlation analysis was conducted with odor response values and it was found that after high-temperature drying and processing, the long-chain alkanes in ginger were decomposed into short-chain alkanes, and the sulfur compounds increased. After the dried ginger was sanded and ironed, it increased in the baked ginger as more stable benzene and aromatic amine components.

CONCLUSION The changes of color, odor and chemical composition of Gansu ginger, dried ginger and baked ginger are studied by electronic nose, electronic eye and GC-MS, which provide reference for identification and quality evaluation of traditional Chinese medicine.