## 3 Results and Discussion  
The chemical compositions of WF and GCB used in this study have previously been described [14]. The major phenolic in GCB used for functional bread production was 5-caffeoylquinic acid (5-CQA; 39.92 mg/g DW). Significant amounts of 5-feruloylquinic acid (5-FQA), 4-caffeoylquinic acid (4-CQA), and 3-feruloylquinic acid (3-FQA) were also found. The dominant fraction of phenolic acids in WF consists of trans- and cis-ferulic acids (257 and 165.57 mg/100 g DW, respectively) [20]. As presented in Table 1, baking increased ferulic acid content (compared to WF). These results were in accordance with literature data [21]. Moreover, the GCB flour addition significantly enriched wholemael wheat bread with 5-CQA (Table 1). A key factor in the activity of plant phenolic compounds is their bioavailability, and this was determined based on the model of the human gastrointestinal tract. We confirmed that both raw materials contain potentially bioaccessible and bioavailable compounds able to protect lipids against oxidation. In cases of potentially mastication-extractable (BE) and bioavailable (AE) compounds, higher activity was found for samples obtained from green coffee. Unexpectedly, the activity of bioaccessible in vitro (DE) compounds derived from both raw materials (i.e., GCB and WF) was comparable. Importantly, the activity of bioaccessible and bioavailable in vitro compounds able to protect lipids against oxidation from both raw materials was higher than those obtained for buffer extracts (Figure 1B). Experiments conducted in a rat model showed that CGAs are not hydrolyzed in the stomach but absorbed in intact form. Based on the Caco-2 intestine epithelial cultured monolayer, a passive diffusion was indicated. Similar results were observed with caffeic acid, which is absorbed both from paracellular diffusion as well by a monocarboxylic acid transporter (MCT). Strong evidence exists that the majority of CGA is not absorbed in the proximal part of the gastrointestinal tract, unless transformed to caffeic and ferulic acids before being absorbed. At present, the influence of the type of food matrix, which influences CGA digestion and bioavailability, remains unclear and represents an interesting area for more research on factors that influence the bioaccessibility of CGAs and other important dietary polyphenols [22]. \begin{table}
\begin{tabular}{c c c c} \hline  & _trans_**-FA** & _cis_**-FA** & **5-CQA** \\ \hline C & 341.81 \(\pm\) 3.21 \({}^{\text{a}}\) & 220.21 \(\pm\) 7.09 \({}^{\text{a}}\) & nd \\ \hline GC1 & 338.41 \(\pm\) 5.88 \({}^{\text{b}}\) & 219.01 \(\pm\) 6.95 \({}^{\text{b}}\) & 322.38 \(\pm\) 14.85 \({}^{\text{a}}\) \\ \hline GC2 & 335.97 \(\pm\) 5.48b \({}^{\text{c}}\) & 214.94 \(\pm\) 5.82 \({}^{\text{c}}\) & 644.76 \(\pm\) 15.11 \({}^{\text{b}}\) \\ \hline GC3 & 332.82 \(\pm\) 5.78 \({}^{\text{d}}\) & 213.58 \(\pm\) 3.64 \({}^{\text{d}}\) & 895.5 \(\pm\) 12.57 \({}^{\text{c}}\) \\ \hline GC4 & 325.46 \(\pm\) 6.01 \({}^{\text{e}}\) & 210.32 \(\pm\) 3.88 \({}^{\text{e}}\) & 1325.34 \(\pm\) 34.21 \({}^{\text{d}}\) \\ \hline GC5 & 323.62 \(\pm\) 4.85 \({}^{\text{f}}\) & 208.56 \(\pm\) 2.45 \({}^{\text{f}}\) & 1647.72 \(\pm\) 46.32 \({}^{\text{e}}\) \\ \hline \end{tabular} C—control bread, GC1–GC5—broad with 1–5 g/100 g green coffee bean addition, respectively, _trans_-FA—_trans_ ferulic acid, _cis_-FA—_cis_ ferulic acid, 5-CQA—5-caffeoylquinic acid, Results were expressed as mean \(\pm\) SD (\(n\) = 9). The values designated in columns by the different letters (\({}^{\text{e}}\), \({}^{\text{b}}\), \({}^{\text{c}}\)) are significantly different (\(p<0.05\)).  
\end{table} 
Table 1: Ferulic and chlorogenic acids content (\(\mu\)g/g DW) in control bread and bread enriched with green coffee flour addition. Figure 1: Lipids-preventing (LPO) potential of green coffee beans and wholeemal wheat flour component in comparison with pure ferulic and chlorogenic acids.