Comparative analysis of optical characterization parameters for tea oil forensics

[Objective] In order to compare the ability of optical characteristic parameters [absorption coefficient （<i>μ</i>_a） and approximate scattering coefficient （<i>μ</i>′_s）] to identify adulterated tea oil and to explore the enhancement effect of the combination of extraction methods on the model to achieve a faster and more accurate identification of different kinds of adulterated oils. [Methods] In this study, vegetable oils were used as experimental materials to prepare adulterated tea oils with different mass fractions. Different preprocessing methods were used to preprocess the optical characteristic parameter data, followed by feature band extraction and subsequent establishment of a Random Forest （RF） qualitative identification model. [Results] After CRAS and UVE-CARS feature extraction, the identification accuracies of the models built using <i>μ</i>_a and <i>μ′</i>_s were 95.65%, 95.65%, and 98.55%, 97.10%, respectively. The combined extraction method （UVE-CARS） resulted in an improvement of at least 1.45 percentage points in the identification results of the models compared with the CARS feature extraction method. [Conclusion] The identification of different adulterated types of tea oil can be realized more quickly and accurately by using <i>μ</i>_a. The combined extraction method can effectively improve the identification ability of the model.