Rapid analysis of flaxseed oil quality during frying process based on Raman spectroscopy combined with peak-area-ratio method

To achieve real-time and rapid monitoring of quality changes in flaxseed oil during frying, we designed three types of experiments including variations in frying temperatures, times, and durations. Raman spectra and two physicochemical indicators of the oil samples were acquired. The frying oil quality was analysed by combining the Raman spectral intensity, peak intensity ratio, and peak area ratio. The results of the peak-area-ratio method showed that the acid value is related to the characteristic peak areas at 1022 cm−1 and 1745 cm−1 in three types of experiments. The peroxide value is related to the ratio of S1078/S970 in temperature-variation category and the ratio of S1300/S1655 in times- and duration-variation category. Additionally, significant differences in the quality of flaxseed oil with varying conditions were observed. Finally, a quality model (CQ) for frying oil using Raman spectroscopy combined with the peak-area-ratio method was proposed. The correlation coefficient between the CQ quality factor established based on Raman spectroscopy and multivariate analysis established by acid value and peroxide value was R2 = 0.99179. The comprehensive quality can be used to quickly and nondestructively determine quality changes in flaxseed oil during the frying process. Therefore, the proposed technique offers a rapid, accurate, and non-destructive approach to analysing the quality changes of flaxseed oil during frying and provides robust technical support for the real-time and rapid detection of flaxseed oil quality alterations.