# Thermal and Kinetic Properties of Brazilian Coffee Arabica Beans
## 3 Results and Discussion
### Analysis of Fatty Acids Profile  
The percentage contribution of six major fatty acids identified in coffee fat samples is presented in Table 5. The chromatograms of fatty acids profile in Brazilian Coffee arabica beans are given in Figure 3.  
In total, these six fatty acids represent about 97% of all the fatty acids detected in the samples. The fat extracted from coffee samples contained from 9.8 to 10.7% of monounsaturated fatty acids (MUFA) and from 42.9 to 43.7% of saturated fatty acids (SFA). The predominant fatty acid present in coffee beans was linoleic acid followed by palmitic acid, with contributions ranging from 41.6 to 41.9% and 30.9 to 31.2%, respectively. Additionally, the analysed coffee fats were comprised of 43.1 to 43.6% polyunsaturated fatty acids (PUFA) including essential fatty acids from \(n\)-3 and \(n\)-6 groups as \(\alpha\)-linolenic acid and linoleic acids. These observations agree with other reported data [10; 40]. From all of the identified fatty acids, the PUFA fraction is, especially, very important considering the nutritional value. Omega-3 and omega-6 fatty acids are essential fatty acids that cannot be produced in the human organism because of the lack of endogenous enzymes. Omega-6 PUFA decrease the LDL fraction of the cholesterol, while omega-3 PUFA have a variable effect on total cholesterol, LDL and HDL fractions of cholesterol and can lower triacylglycerlevel levels [41]. The analysed coffee fat samples contain the omega-6 omega-3 ratio on the very high level of about 27:1. Due to modern agricultural trends, Western diets contain abundant levels of omega-6 PUFA with very low levels of omega-3 PUFA. According to some authors, the omega-6:omega-3 ratio in modern diets can be as high as 20:1, while the proper ratio during human evolution was closer to 1:1. It should be pointed out that a ratio of above 10:1 in the diet can have an adverse effect on human health [42; 43]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameter** & **a** & **b** & **R2** & **Ea** & **Z** \\ \hline Green coffee & & & & & \\ Value for T\({}_{\text{on}}\) & \(-\)5169.5 & 12.5 & 0.99 & 94.11 & 5.63-10\({}^{10}\) \\ Value for T\({}_{\text{max}}\) & \(-\)1687.6 & 4.3 & 0.97 & 30.72 & 1.047-10\({}^{3}\) \\ Light roasted & & & & & \\ Value for T\({}_{\text{on}}\) & \(-\)5471.6 & 12.8 & 0.99 & 99.6 & 1.03-10\({}^{11}\) \\ Value for T\({}_{\text{max}}\) & \(-\)1797.6 & 4.3 & 0.99 & 32.7 & 1.210-10\({}^{3}\) \\ Dark roasted & & & & & \\ Value for T\({}_{\text{on}}\) & \(-\)5779.8 & 13.6 & 0.96 & 105.2 & 7.01-10\({}^{11}\) \\ Value for T\({}_{\text{max}}\) & \(-\)1589.8 & 3.9 & 0.99 & 28.9 & 5.36-10\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Statistical and kinetic parameters characterizing the thermal-oxidative decomposition of coffee fat. Ea—activation energy (kJ mol\({}^{-1}\)); Z—pre-exponential factor. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Common Name** & **Lipid Number** & \multicolumn{3}{c}{**\% of Fatty Acids Peaks Area**} \\ \cline{3-5}  & & **Green Coffee** & **Light Roast** & **Dark Roast** \\ \hline Palmitic acid & 16:0 & 31.64 \(\pm\) 0.14 a & 31.18 \(\pm\) 0.18 a & 30.88 \(\pm\) 0.22 a \\ Stearic acid & 18:0 & 8.71 \(\pm\) 0.13 a & 8.72 \(\pm\) 0.02 a & 8.8 \(\pm\) 0.04 a \\ Oleic acid & 18:1(9) & 9.79 \(\pm\) 0.10 a & 10.49 \(\pm\) 0.01 b & 10.69 \(\pm\) 0.01 b \\ Linoleic acid & 18:2(9,12) & 41.61 \(\pm\) 0.17 a & 41.71 \(\pm\) 0.02 a & 41.94 \(\pm\) 0.07 a \\ \(\alpha\)-Linolenic acid & 18:3(9,12,15) & 1.54 \(\pm\) 0.04 a & 1.69 \(\pm\) 0.02 b & 1.71 \(\pm\) 0.01 b \\ Arachidic acid & 20:0 & 3.38 \(\pm\) 0.03 a & 3.31 \(\pm\) 0.07 a & 3.24 \(\pm\) 0.05 a \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The fatty acids profile in coffee fat sample. (\(\pm\)) standard deviation (SD) from triplicate measurements. Data denoted by the same letter are not statistically different (\(\alpha\) = 0.05) in terms of roasting degree.