UV-Vis spectroscopy combined with chemometrics for discriminating gamma-irradiated Javanese long pepper (

Javanese long pepper ( Piper retrofractum Vahl) is an Indonesian spice known for its main bioactive compound, piperine, which exhibits various pharmacological properties. This study aimed to develop a rapid, non-destructive analytical approach to classify Javanese long pepper extracts exposed to different doses of gamma irradiation using UV-Vis spectroscopy combined with chemometrics. The absorption spectra of 25 extract samples treated with irradiation doses of 0, 250, 500, 750, and 1000 kGy were recorded in the wavelength range of 200–700 nm. Partial Least Squares–Discriminant Analysis (PLS- DA) and Hierarchical Cluster Analysis (HCA) were applied to identify spectral variations and construct classification models. The chemometric models successfully differentiated between non-irradiated and irradiated extracts, indicating that gamma irradiation significantly influenced the UV-Vis spectral characteristics of the samples. These findings demonstrate that combining UV-Vis spectroscopy and multivariate analysis provides a reliable and efficient method to monitor irradiation-induced changes in P. retrofractum extracts. This approach offers potential applications for quality control and authentication of irradiated herbal materials.