Determination of the Fatty Acid Composition in Tree Peony Seeds Using Near-Infrared Spectroscopy

Tree peonies (Paeonia Sect Moutan DC) are an emerging oil crop because of their high oil and alpha-linolenic acid (ALA) content. This research was to investigate the potential use of near infrared reflectance spectroscopy (NIRS) for estimating the major fatty acids contents, such as palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3) in tree peonies. A total of 115 small seed samples and 447 single seeds were selected to calibrate the predictive models. NIRS absorbance spectra were collected using a Fourier transform near infrared (FT-NIR) spectrometer for the small seed samples, and acousto-optic tunable filter-near infrared (AOTF-NIR) for the single seed samples. Statistical analysis was performed with partial least squares (PLS). For the husked samples, C18:3, C18:1 and C18:2 showed the highest correlation coefficient of validation (R (v); = 0.9756, 0.9467 and 0.8485, respectively) and the ratio of performance to deviation (RPD; = 3.58, 1.91 and 2.17, respectively); however, C16:0 did not reach expectations (R (v) = 0.7783, RPD = 1.32). For intact samples, C18:3 showed the best prediction (R (v) = 0.9096, RPD = 3.14), followed by C18:2 (R (v) = 0.8479, RPD = 1.96). The results for C18:1 were poor (R (v) = 0.7237, RPD = 1.70). For single seeds, only the results for C18:3 (R = 0.9150, RPD = 1.73) were good in the husked seed samples. It was concluded that NIRS can be used to rapidly assess the content of the major fatty acids in small samples.