Fig. 1. Trend chart of quality indicators of olive oil heating
(a): Change in acid value; (b): Change in peroxide value; (c): Change in linolenic acid

Fig. 2. Raman spectra of olive oil under different processing conditions

Fig. 3. The relationship between the predicted value and the actual value of the calibration set
(a): The acid value correction set of the PLS method; (b): The acid value correction set of the VAPLS method;(c): Peroxide value correction set of PLS method; (d): Peroxide value correction set of VAPLS metion;(e): Linolenic acid correction set of PLS metion; (f): Linolenic acid correction set of VAPLS metion

Table 1. Model evaluation results under full spectrum

Table 2. Model evaluation results after spectral preprocessing

Table 3. Evaluation results of acid value model

Table 4. Model evaluation results of peroxide value

Table 5. Model evaluation results of linolenic acid