# Identification, Geographical Traceability, and Thermal Oxidation and Photodegradation Studies of Camellia Oil Based on Raman Spectroscopy

## TL;DR

This study uses Raman spectroscopy to identify, trace the origin, and assess the stability of camellia oil, providing a non-destructive method for quality control.

## Contribution

The study introduces a novel integration of Raman spectroscopy with chemometric methods for camellia oil authentication and traceability.

## Key findings

- PLS-DA successfully distinguished camellia oil using Raman bands near 1250 cm−1 and 1650 cm−1.
- A unique peak at 1525 cm−1 in samples from Gongcheng, Guangxi, was identified as a geographical marker linked to carotenoids.
- UV exposure caused rapid degradation of carotenoids, as indicated by the decline of the 1525 cm−1 peak.

## Abstract

Camellia oil, rich in monounsaturated fatty acids, squalene, tocopherols, and polyphenols, is highly valued for its nutritional benefits. However, its high market value and regional variations have led to frequent adulteration, highlighting the need for rapid, non-destructive methods for authentication, geographical traceability, and quality assessment. This study employed portable Raman spectroscopy combined with Partial Least Squares Discriminant Analysis (PLS-DA) and Multivariate Curve Resolution–Alternating Least Squares (MCR-ALS) to differentiate camellia oil from other edible oils and evaluate its thermal and photo-oxidative stability. PLS-DA, based on VIP-selected spectral variables, effectively distinguished camellia oil, with Raman bands near 1250 cm−1 and 1650 cm−1 contributing significantly. A unique peak at 1525 cm−1, observed in samples from Gongcheng, Guangxi, was associated with carotenoids and served as a potential marker for geographical traceability. MCR-ALS modeling revealed significant reductions in the 1650 cm−1 and 1525 cm−1 peaks when temperatures exceeded 150 °C, indicating degradation of unsaturated fatty acids and carotenoids. Under UV exposure, the 1525 cm−1 peak declined sharply and nearly disappeared after 24 h, suggesting rapid carotenoid degradation via photooxidation. Extended UV treatment also affected the 1650 cm−1 peak and led to oxidative product accumulation. Overall, this study demonstrates the feasibility of integrating Raman spectroscopy with chemometric analysis for efficient oil classification, traceability, and stability monitoring, offering a valuable tool for food quality control and market supervision.