Abstract: In order to evaluate the quality change of edible oils during storage, terahertz attenuated total reflection (THz-ATR) spectroscopy was used for the non-destructive identification of oils with different oxidation degrees. First, the effect of storage conditions on the quality of edible oils was explored, and then according to the national standard definition of edible oil quality, the collected samples were divided into fresh oil, edible oil and inedible oil. Terahertz time-domain spectra of these oils were collected. After data preprocessing, the euclidean distance matching method was used to identify the refractive index spectra of edible oils with an accuracy of 95.65%, and linear discriminant analysis (LDA) was used to identify the absorption coefficient spectra with an accuacy of 91.00%. Comparative analysis demonstrated that both models exhibited desired recognition accuracy. This study may provide a theoretical basis for the analysis of various quality attributes of edible oil by terahertz spectroscopy.

Key words: edible oil; terahertz spectroscopy; oxidation; qualitative analysis; storage conditions