Comprehensive Investigation of Thermal Degradation Characteristics and Properties Changes of Plant Edible Oils by FTIR-Spectroscopy

Abstract

Structural characterization of edible oils after thermal treatment was made by (FTIR) spectroscopy. Olive, corn and sunflower oil samples were thermally treated at three consecutive cycles. Each cycle consisted of heating at the boiling point for 8 h, followed by cooling at room temperature for 16 h. At the end of each cycle the characteristics of oils were studied by FTIR spectroscopy and standard methods. Study of FTIR spectra of the treated oils revealed that the heating of oils caused significant changes in the intensities of their bands and produced shifts in the position of specific bands such as 3008 cm−1 and 1745 cm−1. The level of oil oxidation during different heating period was followed by the absorbance ratio at 3530/3472 cm−1. Additionally, the absorbance ratio 2853/3008 cm−1 was used as a measure of degree of unsaturation. The thermal heating of oils produced an initial decrease in the specific absorbance ratios which could be attributed to the reduction of unsaturated fatty acid content due to oxidation process. The results in this study demonstrated that FTIR could be used for assessment of the state of oils by using specific absorbance ratios as indicators.

Influence of coffee brewing methods on the chromatographic and spectroscopic profiles, antioxidant and sensory properties

“…Additionally, so-called coffee oil contains kaurene esterified diterpenes in proportions of up to 20% of the total lipids. Coffee lipid components are of interest due to their antioxidant, antimicrobial, antiproliferative activity (sterols, tocopherols, free diterpenes, waxes), anti-inflammatory properties and potential anticarcinogenic effects (diterpenes: cafestol and kahweol) 26 , 27 . Lipids also contribute to the formation of the aroma and flavour of coffee drinks, which is especially important for coffee consumers.…”

Exploring the Potential of Grape Pomace Extract to Inhibit Thermo-Oxidative Degradation of Sunflower Oil: From Routine Tests to ATR-FTIR Spectroscopy

“…In this regard, attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, one of the most well-known spectroscopic techniques which works well in the middle infrared region, has been applied for the characterization of the oxidation degree of heat-treated edible oils [ 27 , 28 , 29 ]. FTIR spectroscopy has been successfully used in recent years for the rapid monitoring of the oxidative status of heat-treated vegetable oils based on the vibrations of different chemical groups that occur at specific wavelengths in the infrared spectrum.…”

Chemical Changes of Pumpkin Seed Oils and the Impact on Lipid Stability During Thermal Treatment: Study by Ftir - Spectroscopy

“…If double bonds are part of triglyceride compounds in that case could be used ratio 3007/1745 (Figure 4), because peak 1745 cm -1 it is a vibration of carbonyl group (C=O) ester functional group, representative as triglyceride compounds (Rexhepi al., 2019;Guillen & Cabo, 2000). This ratio could be used as a second confirmation indicator for lipid peroxidation because vegetable oils composition is more than 95 % triglyceride and usually most of double bonds are part of triglyceride (Hoffmann et al, 2018).…”

“…These researchers emphasize the importance of studies on the oxidative behaviour after roasting of pumpkin seeds, as many antioxidant compounds are present after the roasting process. FTIR -Spectroscopy, as a sensitive tool for monitoring lipid peroxidation, was applied using ratio intensity of different frequencies, to verify chemical correlations (Rexhepi et al, 2019;Guillen & Cabo, 2000). This tool has also been used to detect the Maillard Reaction by monitoring the intensity of the carbonyl group of triglycerides and methylene group of aliphatic hydrocarbons.…”