Spectral investigation of aspartame and acesulfame utilizing PXRD, Raman, FTIR, and THz technologies

Artificial sweeteners, as a type of food additive, have vibration frequencies mostly concentrated in the terahertz (THz) band, which enables us to utilize THz technology to deeply analyze their molecular properties. To gain a more comprehensive understanding of the features of artificial sweeteners, this study specifically chose aspartame and acesulfame as representatives. Initially, we employed PXRD and Raman spectroscopy techniques to carry out a thorough examination and verification of the crystalline structure as well as the purity levels of these two synthetic sweeteners. Then, with the aid of Fourier transform infrared spectroscopy (FTIR) technology and terahertz time-domain spectroscopy (THz-TDS) system, the spectral characteristics of aspartame and acesulfame were precisely measured. Moreover, the crystal configurations of these two artificial sweeteners were simulated using solid-state density functional theory (DFT), and the simulation results were in good agreement with the experimental results, further validating the effectiveness of our research methods. Finally, using microfluidic chip technology, the THz spectral characteristics of aspartame and acesulfame in solution were determined, and were compared with their spectra in solid state. We found that the THz spectra of the two artificial sweeteners in solid and solution states have significant correlations. In addition, the research further elucidated that the THz spectrum of a substance dissolved in a solution exhibits a close correlation with its concentration within that solution. These findings provide new perspectives and value for our in-depth research on artificial sweeteners.