Skip to main content

Applications of FTIR and chemometrics methods in authenticity analysis of walnut oil


This study focuses on detecting and evaluating the adulteration in nut oil, which can cause health and food dangers. The two adulterants used during this study are cheaper vegetable oils and present a similar property with walnut oil, sunflower oil with a falsification percentage of 5.80–31.95%, and rapeseed oil with 4.33–29.37%. This adulteration was studied using Fourier transform infrared spectroscopy (FTIR) coupled with chemometrics, a new and specific approach. The spectra of the studied samples were determined by FTIR and were thermometrically analyzed by PLSR and PCR with two sorts of pretreatment, normalization, and first derivation. The results showed different functional groups of the nut oil. The most appropriate pretreatment that provides reliable calibration values (RMSE) and prediction (RMSEP) is the normalization preprocessing in the range of 3050 to 700 cm−1. The chemometrics results give the best model selected in the PLSR with an R2 of 0.998 for sunflower oil and 0.999 for rapeseed oil. According to this study, we have solved nut oil falsification by developing a chemometrics model that can detect and evaluate this adulteration.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5


  1. I. Oliveira, A. Sousa, I.C.F.R. Ferreira, A. Bento, L. Estevinho, J.A. Pereira, Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks. Food Chem Toxicol 46(7), 2326–2331 (2008).

    CAS  Article  Google Scholar 

  2. M.A. Rather, B.A. Dar, M.Y. Dar, B.A. Wani, W.A. Shah, B.A. Bhat, B.A. Ganai, K.A. Bhat, R. Anand, M.A. Qurishi, Chemical composition, antioxidant and antibacterial activities of the leaf essential oil of Juglans regia L. and its constituents. Phytomedicine 19(13), 1185–1190 (2012).

    CAS  Article  Google Scholar 

  3. J.A. Pereira, I. Oliveira, A. Sousa, P. Valentão, P.B. Andrade, I.C.F.R. Ferreira, F. Ferreres, A. Bento, R. Seabra, L. Estevinho, Walnut (Juglans regia L.) leaves: Phenolic compounds, antibacterial activity and antioxidant potential of different cultivars. Food Chem Toxicol 45(11), 2287–2295 (2007).

    CAS  Article  Google Scholar 

  4. F. Stampar, A. Solar, M. Hudina, R. Veberic, M. Colaric, Traditional walnut liqueur – Cocktail of phenolics. Food Chem 95(4), 627–631 (2006).

    CAS  Article  Google Scholar 

  5. M. Carvalho, P.J. Ferreira, V.S. Mendes, R. Silva, J.A. Pereira, C. Jerónimo, B.M. Silva, Human cancer cell antiproliferative and antioxidant activities of Juglans regia L. Food Chem Toxicol 48(1), 441–447 (2010).

    CAS  Article  Google Scholar 

  6. P. Gao, R. Liu, Q. Jin, X. Wang, Comparative study of chemical compositions and antioxidant capacities of oils obtained from two species of walnut: Juglans regia and Juglans sigillata. Food Chem 279, 279–287 (2019).

    CAS  Article  Google Scholar 

  7. P. Gao, R. Liu, Q. Jin, X. Wang, Effects of processing methods on the chemical composition and antioxidant capacity of walnut (Juglans regia L.) oil. LWT 135, 109958 (2021).

    CAS  Article  Google Scholar 

  8. J.S. Amaral, S. Casal, J.A. Pereira, R.M. Seabra, B.P.P. Oliveira, Determination of sterol and fatty acid compositions, oxidative stability, and nutritional value of six walnut (Juglans regia L.) cultivars grown in Portugal. J Agric Food Chem 51(26), 7698–7702 (2003).

    CAS  Article  Google Scholar 

  9. A. Benamar, F. Mahjoubi, G.A. Ali, F. Kzaiber, A. Oussama, A chemometric method for contamination sources identification along the Oum Er Rbia river (Morocco). Bul Chem Commun 52(1), 159–171 (2020)

    Google Scholar 

  10. M. El Mouftari, F.Z. Mahjoubi, F. Kzaiber, W. Terouzi, G.A.M. Ali, S. Souhassou, A. Oussama, Study of oleaster oil’s falsification by aTR-FTIR and chemometrics tools. Egypt J Chem 64(6), 2747–2755 (2021)

    Google Scholar 

  11. B. Li, H. Wang, Q. Zhao, J. Ouyang, Y. Wu, Rapid detection of authenticity and adulteration of walnut oil by FTIR and fluorescence spectroscopy: A comparative study. Food Chem 181, 25–30 (2015).

    CAS  Article  Google Scholar 

  12. A. Oussama, F. Elabadi, S. Platikanov, F. Kzaiber, R. Tauler, Detection of olive oil adulteration using FT-IR spectroscopy and PLS with variable importance of projection (VIP) scores. J Am Oil Chem Soc 89(10), 1807–1812 (2012).

    CAS  Article  Google Scholar 

  13. P. Liang, H. Wang, C. Chen, F. Ge, D. Liu, S. Li, B. Han, X. Xiong, S. Zhao, The use of Fourier transform infrared spectroscopy for quantification of adulteration in virgin walnut oil. J Spectrosc 2013, 305604 (2013).

    CAS  Article  Google Scholar 

  14. A. Hirri, M. Bassbasi, S. Souhassou, F. Kzaiber, A. Oussama, Prediction of polyphenol fraction in virgin olive oil using mid-infrared attenuated total reflectance attenuated total reflectance accessory–Mid-infrared coupled with partial least squares regression. Int J Food Prop 19(7), 1504–1512 (2015).

    CAS  Article  Google Scholar 

  15. L. Wang, F. Lee, X. Wang, Y. He, Feasibility study of quantifying and discriminating soybean oil adulteration in camellia oils by attenuated total reflectance MIR and fiber optic diffuse reflectance NIR. Food Chem 95(3), 529–536 (2006).

    CAS  Article  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to M. El Mouftari.

Ethics declarations

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

El Mouftari, M., Essafi, I., Khalidi, A. et al. Applications of FTIR and chemometrics methods in authenticity analysis of walnut oil. emergent mater. 5, 167–174 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • FTIR
  • Chemometrics
  • Nut oil
  • Adulteration
  • Sunflower oil
  • Rapeseed oil