title: Classification and quantification analysis of peach kernel from different origins with near-infrared diffuse reflection spectroscopy.
abstract: BACKGROUND
  Peach kernels which contain kinds of fatty acids play an important role in the regulation of a variety of physiological and biological functions.
  
  
  OBJECTIVE
  To establish an innovative and rapid diffuse reflectance near-infrared spectroscopy (DR-NIR) analysis method along with chemometric techniques for the qualitative and quantitative determination of a peach kernel.
  
  
  METHODS
  Peach kernel samples from nine different origins were analyzed with high-performance liquid chromatography (HPLC) as a reference method. DR-NIR is in the spectral range 1100-2300 nm. Principal component analysis (PCA) and partial least squares regression (PLSR) algorithm were applied to obtain prediction models, The Savitzky-Golay derivative and first derivative were adopted for the spectral pre-processing, PCA was applied to classify the varieties of those samples. For the quantitative calibration, the models of linoleic and oleinic acids were established with the PLSR algorithm and the optimal principal component (PC) numbers were selected with leave-one-out (LOO) cross-validation. The established models were evaluated with the root mean square error of deviation (RMSED) and corresponding correlation coefficients (R (2)).
  
  
  RESULTS
  The PCA results of DR-NIR spectra yield clear classification of the two varieties of peach kernel. PLSR had a better predictive ability. The correlation coefficients of the two calibration models were above 0.99, and the RMSED of linoleic and oleinic acids were 1.266% and 1.412%, respectively.
  
  
  CONCLUSIONS
  The DR-NIR combined with PCA and PLSR algorithm could be used efficiently to identify and quantify peach kernels and also help to solve variety problem.
authors.affiliation: State Key Laboratory of Newtech for Chinese Mdeicine Pharmaceutical Process, Jiangsu Kanion Pharmaceutical Co. Ltd., Lianyungang, Jiangsu Province, 222001, China ; College of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian Liaoning province, 116600, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Newtech for Chinese Mdeicine Pharmaceutical Process, Jiangsu Kanion Pharmaceutical Co. Ltd., Lianyungang, Jiangsu Province, 222001, China.
authors.forename: Zhen-Zhong
authors.initials: ZZ
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Newtech for Chinese Mdeicine Pharmaceutical Process, Jiangsu Kanion Pharmaceutical Co. Ltd., Lianyungang, Jiangsu Province, 222001, China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Qing
authors.affiliation: State Key Laboratory of Newtech for Chinese Mdeicine Pharmaceutical Process, Jiangsu Kanion Pharmaceutical Co. Ltd., Lianyungang, Jiangsu Province, 222001, China.
authors.forename: Hong-Juan
authors.initials: HJ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Newtech for Chinese Mdeicine Pharmaceutical Process, Jiangsu Kanion Pharmaceutical Co. Ltd., Lianyungang, Jiangsu Province, 222001, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
keywords: Linoleic acid; multivariate modeling; near-infrared spectroscopy; oleic acid; peach kernel