Photoacoustic (PA) spectroscopy in the ultraviolet and visible was demonstrated to be a suitable tool for direct determination of total phenolic content in red sorghum flours. The PA spectra obtained feature two characteristic peaks: the first centered at 285 nm is due to the aromatic amino acids, while the second one at 335 nm is associated with the total phenolic content. The outcome of the PA study was compared with the results obtained by a conventional, tedious Folin-Ciocalteau chemical method. Statistical analysis indicates no significant difference between the two methods used in this study.
Doka, O., Bicanic, D. D., Dicko, M. H., & Slingerland, M. A. (2004). Photoacoustic approach in direct determination of the total phenolic content in Red Sorghum Flours. Journal of Agricultural and Food Chemistry, 52(8), 2133-2136. https://doi.org/10.1021/jf030421a