Differentiation of Gelsemium elegans-Containing Toxic Honeys and Non-Toxic Honeys by Near Infrared Spectroscopy Combined with Aquaphotomics

This work proposes a fast and accurate method based on near-infrared (NIR) spectroscopy with partial least-squares discriminant analysis (PLS-DA) and aquaphotomics to identify toxic honeys. PLS-DA was used to construct an optimal model for distinguishing toxic honey from a non-toxic honey. The models based on preprocessed NIR spectra have an accuracy of 92.73% and were more accurate than the model based on raw NIR spectra. Based on the aquaphotomics analysis of the first overtone of water (1300–1600 nm), we found that the 1398 nm, 1440 nm, and 1472 nm bands can be used as markers to distinguish toxic honeys. Compared to non-toxic honeys, gelsemium elegans -containing toxic honeys have a significantly smaller number of water molecules with multiple hydrogen bonds, due to the hydrogen bonding of the C–O–C, C = O, and NH₂ groups of gelsemine and koumine. These groups replace hydrogen bonds between glucose/polysaccharide molecules and water.