MONITORING OXIDATIVE LEVELS OF FRYING OILS USING FTIR SPECTROSCOPY AND MULTIVARIATE CALIBRATION
Objective: To develop a rapid reliable technique based on Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy in combination with multivariate calibrations for prediction of frying oil quality, namely acid value (AV), iodine value (IV) and peroxide value (PV).
Methods: FTIR spectra were directly obtained and subjected to optimization and spectral treatments including a selection of wavenumbers region and spectral derivatization. The condition selected was based on its capability to provide the highest coefficient of determination (R2) and the lowest root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) for the relationship between actual values of AV, IV, and PV as determined using standard titrimetric methods and predicted values as determined by FTIR spectroscopy aided with multivariate calibrations.
Results: Using optimized condition, FTIR spectroscopy combined with multivariate calibrations could be successfully used for prediction of AV, and PV. Acid value (AV) could be determined using the first derivative spectra at wavenumbers of 1524-658 cm-1. The R2of 0.973 (in calibration model) and 0.932 (in prediction model) with low RMSEC and RMSEP values was obtained. Iodine value (IV) was best predicted using principle component regression (PCR) with normal FTIR spectra at the combined wavenumbers region of 3076-2783 and 1811-656 cm-1. PCR using normal spectra at combined wavenumbers region of 3076-2783and 1811-656 cm-1 was also selected for prediction of PV.
Conclusion: FTIR spectroscopy in combination with multivariate calibration has been successfully used for prediction of acid value, iodine value and peroxide value in frying oils. The developed method could be an alternative technique for analysis of these values to perform quality assurance of frying oils.
2. Blumenthal MM. A new look at the chemistry and physics of deep-fat frying. Food Technol 1991;45:68â€“71.
3. White PJ. Methods for measuring changes in deep-fat frying oils. Food Technol 1991;45:75â€“80.
4. Zhang H, Ma J, Miao Y, Tuchiya T, Chen JY. Analysis of carbonyl value of frying oil by fourier transform infrared spectroscopy. J Oleo Sci 2015;64:375-80.
5. Yu X, van de Voort FR, Sedman J. Determination of peroxide value of edible oils by FTIR spectroscopy with the use of the spectral reconstitution technique. Talanta 2007;74:241-6.
6. Rohman A. The use of infrared spectroscopy in combination with chemometrics for quality control and authentication of edible fats and oils: a review. Appl Spectros Rev 2017;52:589-604.
7. Rohman A, Che Man YB, Mohd Yusof F. The use of FTIR spectroscopy and chemometrics for rapid authentication of extra virgin olive oil. J Am Oil Chem Soc 2014;91:207â€“13.
8. Yuliani F, Riyanto S, Rohman A. Application of FTIR spectra combined with chemometrics for analysis of candlenut oil adulteration. Int J Appl Pharm 2018;10:54-9.
9. Fritsch CW. Measurements of frying fat deterioration: a brief review. J Am Oil Chem Soc 1981;58:272â€“4.
10. Osawa CC, GonÃ§alves LAG, Ragazzi S. Correlation between free fatty acids of vegetable oils evaluated by rapid tests and by the official method. J Food Compos Anal 2007;20:523â€“8.
11. Yu XZ, Du SK, Li ZX, Zhang JY. Study on detection of peroxide value in edible oils using FTIR spectral reconstitution technique. J Chin Institute Food Sci Technol 2011;11:169â€“75.
12. Guillen MD, Cabo N. Fourier transform infrared spectra data versus peroxide and anisidine values to determine oxidative stability of edible oils. Food Chem 2002;77:503â€“10.
13. Kamble VV, Gaikwad NB. Fourier transform infrared spectroscopy spectroscopic studies in Embelia ribes Burm. F.: A vulnerable medicinal plant. Asian J Pharm Clin Res 2016;9:41-7.
14. Jiang X, Li S, Xiang G, Li Q, Fan L, He L, et al. Determination of the acid values of edible oils via FTIR spectroscopy based on the OAH stretching band. Food Chem 2016;212:585â€“9.
15. Du R, Lai K, Xiao Z, Shen Y, Wang X, Huang Y. Evaluation of the quality of deep frying oils with fourier transform near-infrared and mid-infrared spectroscopy. J Food Sci 2012;77:C261â€“6.
16. Liang P, Chen C, Zhao S. Application of fourier transform infrared spectroscopy for the oxidation and peroxide value evaluation in virgin walnut oil. J Spectros 2013;5. http:// dx.doi.org/10.1155/2013/138728
17. Triyasmon L, Riyanto S, Rohman A. Determination of iodine value and acid value of red fruit oil by infrared spectroscopy and multivariate calibration. Int Food Res J 2013;20:3259-63.
18. AOCS Official methods and recommended practices of the American oil chemistsâ€™ society, AOCS Press, Champaign, method Ca 5a-40; 1989.
19. Martens H, Naes T. Multivariate calibration. John Wiley and Sons, Chichester, UK; 1989.
20. Thomas EV. A primer on multivariate calibration. Anal Chem 1994;66:795â€“804.
21. Zhu EY, Yang PY. Chemometrics and its application, Science Press: Beijing, China; 2003.
22. Zhang L, Zhang LM, Li Y, Liu BP, Wang XF, Wang JD. Application and improvement of partial-least-squares in fourier transform infrared spectroscopy. Spectros Spectral Anal 2005;25:1610â€“3.
23. Yun JM, Surh J. Fatty acid composition as a predictor for the oxidation stability of korean vegetable oils with or without induced oxidative stress. Preventive Nutr Food Sci 2012;17:158-65.
24. Dyminska L, Calik M, Albegar AMM, ZajÄ…c A, Kostyn K, Lorenc J, et al. Quantitative determination of the iodine values of unsaturated plant oils using infrared and Raman spectroscopy methods. Int J Food Prop 2017;20:2003-15.
25. Chebet J, Kinyanjui T, Cheplogoi PK. Impact of frying on iodine value of vegetable oils before and after deep frying in different types of food in Kenya. J Sci Innov Res 2016;5:193-6.