[Research on parching procedure of white mustard seed with fourier transform infrared spectroscopy and two-dimensional IR correlation spectroscopy].

Using multi-steps macro-fingerprint infrared (IR) spectroscopy, which combines three steps: conventional Fourier transform infrared spectroscopy (FTIR), second derivative spectroscopy, and two-dimensional infrared (2D-IR) correlation spectroscopy, the authors tracked dynamically the parching procedure of mustard seed to analyze the main transformation during the process. Compared with conventional IR spectra of samples parched for different time, the authors found that the characteristic peaks of protein decreased gradually, indicating the reduction of protein with the parching process, maybe because under a longtime parching procedure the heat denaturation occurred in protein compound. In addition, the essence of enzyme was protein, therefore, its transformation trend was closely related to that of protein, which also underwent heat denaturation. The absorption peak around 1 055 cm(-1), which was due to the vibrations of fibred saccharides, began to minish rapidly at early time, then vanished after ten minutes because of the decomposition of fibred saccharides at the beginning of the process. Moreover the results of second derivative spectroscopy and 2D IR correlation spectroscopy validated that of conventional IR spectroscopy, which also indicated the heat denaturation of enzyme and decomposition of saccharides. This multi-steps macro-fingerprint IR spectroscopy method can track dynamically the processing procedure of medicinal herbs and reveal the main transformations; it must play an important role in studying medicinal herbs in the future.