Investigation on Crude and High-Temperature Heated Coffee Oil by ATR-FTIR Spectroscopy along with Antioxidant and Antimicrobial Properties

Abstract

The coffee oil has a promising potential to be used in food industry, but an efficient use, especially in products that required high-temperature heating, depends on its chemical composition and the changes induced by processing. Since there is little information on this topic, the aim of our study was to investigate the crude green and roasted coffee oil (GCO, RCO) and heated (HGCO, HRCO) for 1 h at 200°C, by Fourier Transform Infrared (FTIR) spectroscopy and in terms of antioxidant and antimicrobial properties. The results of FTIR spectroscopy revealed that no statistically significant differences (one-way ANOVA, p>0.05) in the oxidative status of GCO and RCO were found. The coffee oils heating induced significant spectral changes in the regions 3100–3600 cm–1, 2800–3050 cm–1 and 1680–1780 cm–1 proved by the differences in the absorbance ratios A 3009 cm−1/A 2922 cm−1, A 3009 cm−1/A 2853 cm−1, A 3009 cm−1/A 1744 cm−1, A 1744 cm−1/A 2922 cm−1. These alterations were related to the reduction of the unsaturation degree due to primary and secondary oxidation processes of the lipid fraction. The radical scavenging ability of oils investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed that the IC50 value of GCO was significantly lower than of RCO (p<0.05). The IC50 values of crude coffee oils were lower than those of heated samples. The antioxidant activity of oils was attributed to both antioxidant compounds with free-radical scavenging capacity and to lipids oxidation products generated by heating. In the first 6 h of incubation, the inhibitory activity of crude oils against E. coli and E. faecalis was not significantly different to the control (p>0.05). Also, HGCO and HRCO showed significantly different inhibitory potential related to the control (p<0.05). The heating induced statistically significant decreases in the effectiveness of coffee oils against the tested bacteria. GCO proved to be the most effective among investigated coffee oils against the tested bacteria.

The influence of high-temperature heating on composition and thermo-oxidative stability of the oil extracted from Arabica coffee beans

“…The green and roasted coffee beans used in this study are Coffea arabica L. from Guaxupe Brazil, acquired from a Romanian coffee distributor (SC Global Trade SRL, 24 Constructorului St., Cornetu, Ilfov County, Romania, lot number 922/1456). The procedure for obtaining oil from green and roasted coffee beans is similar to that reported previously in [ 43 ]. Coffee beans samples were ground using a grinder (Grindomix Retsch GM 2000) and passed through a 60 mesh sieve.…”

“…ATR-FTIR spectroscopy analysis performed in a previous study led to the conclusion that, with regard to the oxidation stages of the extracted oil, there are no major differences between green and roasted coffee beans. The study also revealed that, after heating the oils at high temperature, there were changes of the spectral bounds in the regions 3100–3600 cm –1 , 2800–3050 cm –1 and 1680–1780 cm –1 , respectively, which were attributed to primary and secondary oxidation processes of the lipid fraction [ 43 ].…”

Spectroscopic Methods in the Evaluation of Modified Vegetable Base Oils from Crambe abyssinica

“…All recorded spectra showed absorption bands at different wavenumbers, as follows: 3005 cm −1 (γ C-H of cis double bonds =CH), shoulder at 2955 cm −1 (γ C-H of aliphatic CH 3 ), 2922 and 2853 cm −1 (γ C-H of CH 2 ), 1744 cm −1 (γ C=O of ester carbonyl functional groups of triglycerides (O-C=O), weak shoulder at 1719 and 1700 cm −1 (γ C=O of carbonyl functional groups of ketones and free fatty acids, 1655 cm −1 (γ C=C of cis -olefins), 1463, 1458 cm −1 (δ C-H of CH 2 and CH 3 aliphatic groups), 1418 cm −1 (rocking vibration of C-H bonds of cis -disubstiuted olefins), 1397 cm −1 (δ C-H in plane of C-H of cis -olefinic groups), 1376 cm −1 (δ C-H of C-H of CH 2 groups), 1237, 1160, 1118 and 1096 cm −1 (γ C-O of ester groups), 970 cm −1 (δ C=C out-of-plane of disubstituted olefins), 722 cm −1 (overlapping of aliphatic CH 2 rocking vibration and out of plane vibration of cis -disubstituted olefins) [44].…”

Recovery of spent coffee grounds oil using supercritical CO2: Extraction optimisation and physicochemical properties of oil

“…years, scientific and medical communities have paid increasing attention to essential oils, polyphenols, and other natural compounds derived from plants and various biological sources, because of their antioxidant activity and promising influences on human health; for example, anti-tumour and anti-allergic activities, protective action against cancer, cardiovascular disease, and chronic degenerative diseases, including cataracts, macular degeneration, diabetes, and neurodegeneration diseases (Le, Vu, Nguyen, Tran, & Le, 2017;Raba et al, 2015;Ramalakshmi, Rao, Takano-Ishikawa, & Goto, 2009;Rice-Evans, Miller, & Paganga, 1997;Scalbert, Johnson, & Saltmarsh, 2005). Moreover, phenolic compounds have been used for several applications in the food, food supplement, cosmetic, and also pharmaceutical industries.…”

“…Moreover, phenolic compounds have been used for several applications in the food, food supplement, cosmetic, and also pharmaceutical industries. Extraction of oil, phenolic compounds and other antioxidant compounds from spent coffee grounds is considered as an interesting alternative procedure to obtain these compounds from the low-cost solid residue while adding value to spent coffee grounds (Raba et al, 2015).…”