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Chemometric comparison of almond oxidation rates using kinetic parameters obtained by infrared spectroscopy
Author(s) -
Román Falcó Iván P,
Prats Moya María Soledad,
Maestre Pérez Salvador E,
Martín Carratalá Maria L,
Grané Teruel Nuria
Publication year - 2020
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.10513
Subject(s) - absorbance , cultivar , fourier transform infrared spectroscopy , principal component analysis , chemistry , kinetic energy , analytical chemistry (journal) , infrared spectroscopy , linear discriminant analysis , attenuated total reflection , infrared , horticulture , chromatography , mathematics , organic chemistry , statistics , biology , optics , physics , quantum mechanics
BACKGROUND The study of almond fat stability is essential from a quality control perspective meanly because, in most of the cases, almonds are sold skinned and thermally treated. In this work an alternative method to Rancimat test based on attenuated total reflectance‐Fourier‐transform infrared (ATR‐FTIR) spectrometry was adapted for checking the induced degradation at 75 °C of seven almond oil cultivars, three of the top Californian producing varieties, and, four traditional cultivars harvested in Spain. RESULTS The thermal oil degradation evolution was followed by measuring the changes in the absorbance of the selected FTIR spectra bands (3470, 3006, 1730, 1630, 988 and 970 cm −1 ). A first‐order kinetic behaviour was observed, after an induction time in all bands. CONCLUSIONS Kinetic coefficients and induction times were easily obtained as the absorbance values (from difference spectra) fitted to pseudo‐first‐order kinetics after the induction time. Principal component analysis was applied to the kinetic parameters to visualize which variables could be useful to classify the almond cultivars based on their resistance to thermal oxidation processes. It was found that selecting only the induction times corresponding to the bands 3470, 3006, 1630 and 970 cm −1 a separate classification of the Californian cultivars from the Spanish ones was possible. Finally, a linear discriminant analysis was assayed using only the four induction times previously selected. Validated classification and correct in 100% of the cases was obtained for all the samples based on their Spanish or Californian origin. © 2020 Society of Chemical Industry