ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Evaluation of the antioxidant effect of propolis on thermal oxidation of sunflower oil using ATR-MIR spectroscopy

Kubra Gulsen and Gulgun Cakmak-Arslan

Department of Biology, Faculty of Arts and Sciences, Duzce University, Duzce, Turkey

E-mail: gulguncakmak@duzce.edu.tr

Received: 21 December 2022  Accepted: 27 May 2023

Abstract:

This study was conducted to evaluate the effectiveness of propolis in improving the oxidative stability of sunflower oil (SFO) in comparison to buthylated hydroxytoluene (BHT), a synthetic antioxidant, under simulated frying conditions by using Attenuated Total Reflection-Mid Infrared (ATR-MIR) spectroscopy. Control, two different concentrations of propolis (1500 and 2000 ppm) and BHT added SFOs were heated at 180 °C for 24 h (8 h per day) and changes in the spectra of these oils sampled every 2 h were evaluated. The results revealed that the areas of the infrared bands related to primary and secondary oxidation products (the bands at 3482 and 1745 cm⁻¹) and to trans-unsaturated fatty acids (the bands at 987 and 965 cm⁻¹) increased and the areas of the bands related to cis fatty acids (the bands at 3009 and 722 cm⁻¹) decreased in the control SFO spectra after the heating process as a result of oxidation. 2000 ppm propolis delayed all these oxidation process, in a similar manner to BHT. Principal component analysis and chemical studies confirmed that propolis has a protective effect on the thermal oxidation of SFO. These results indicated that propolis could be recommended as an effective natural antioxidant and used instead of synthetic antioxidants in edible oil industry. This study also showed that ATR-MIR spectroscopy could be used as a fast and efficient technique to evaluate the oxidative stability of edible oils and the bands at 3482, 3009, 1745, 987, 965, 722 cm⁻¹ can be used as biomarkers for oxidation.

Graphical Abstract

Keywords: Propolis; Sunflower oil; Oil oxidation; Attenuated total reflection-mid infrared (ATR-MIR) spectroscopy; Oxidative stability; Principal component analysis (PCA)

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02893-2

Chemical Papers 77 (10) 5733–5750 (2023)