## 3 Results and Discussions
### Analysis of Volatile Compounds of Biscuit Samples  
A total number of 21 volatile compounds were identified in the RFSF enriched biscuits, by means of ITEX/GC-MS technique as shown in Table 6. In all biscuit samples, the main volatile compound from the aldehydes group was hexanal, ranging from 14.76% to 18.39%, meanwhile \(\beta\)-myrcrene and D-limonene were the main volatile compounds from terpenes and terpenoids group, ranging from 8.99% to 15.65% and 2.47% to 8.48%, respectively. Acetophenone was the major volatile compound from the ketones group with values between 2.50% to 10.98%, meanwhile, 4-methyloctane reached a final value of 6.92% in the B40 sample. The presence of 4-methyloctane could be justified by the addition of vanilla essence during the biscuit manufacturing [66]. The amount of D-limonene in RFSF increased linearly with increasing levels of RFSF in the final baked products. D-Limonene is responsible for odour perceptions like citrus and mint. Furthermore, flaxseed represent \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mineral Content (mg/100 g, fw)**} & \multicolumn{4}{c}{**Biscuit Samples 1**} \\ \cline{2-5}  & **B0** & **B10** & **B25** & **B40** \\ \hline P & 27.83 \(\pm\) 0.03 a  & 35.64 \(\pm\) 0.39 b  & 43.20 \(\pm\) 0.67 c  & 49.78 \(\pm\) 0.03 d  \\ K & 240.46 \(\pm\) 0.89 a  & 275.38 \(\pm\) 0.76 b  & 313.08 \(\pm\) 0.55 c  & 356.99 \(\pm\) 0.99 d  \\ Cu & N.D. & N.D. & N.D. & N.D. \\ Zn & 0.71 \(\pm\) 0.09 a  & 1.12 \(\pm\) 0.03 b  & 1.54 \(\pm\) 0.05 c  & 1.97 \(\pm\) 0.02 d  \\ Fe & 1.40 \(\pm\) 0.03 a  & 1.87 \(\pm\) 0.05 b  & 2.27 \(\pm\) 0.07 c  & 2.76 \(\pm\) 0.11 d  \\ Mn & N.D. & N.D. & N.D. & N.D. \\ Ca & 164.46 \(\pm\) 0.83 a  & 195.43 \(\pm\) 0.79 b  & 223.05 \(\pm\) 0.85 c  & 256.09 \(\pm\) 0.533 d  \\ Mg & 41.36 \(\pm\) 0.55 a  & 90.16 \(\pm\) 0.59 b  & 141.47 \(\pm\) 0.88 c  & 191.33 \(\pm\) 0.39 d  \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The concentration of macro and microelements in biscuit samples. a high source of carotenoids [67] which could be correlated with higher amounts of D-limonene, as reported by [PERSON] et al. [68]. From the terpenes and terpenoids group apart from D-limonene, \(\beta\)-myrcene enhanced the final odour perception through its balsamic, musty and spice perceptions. Acetophenone, from the ketone group, was previously pinpointed as a volatile compound with implication in the overall flavor of flour products which could be formed during Maillard reactions [69]. Its odour perception is pleasant, having musty, flowery and almond characteristics. The increased amount of heptan-2-one from the ketone group with increasing yield of RFSF could be explained by the chemical composition of flaxseed, rich in tocopherol and ascorbic acid [65]. In this line, [PERSON] et al. [70] showed that tocopherol and ascorbic acid significantly increased the peak area of heptan-2-one. Furthermore, a recent study of [PERSON] and [PERSON] [71] highlighted that benzaldehyde could be formed through chemical reactions such as lipid oxidation. The reaction involved in the first step is a carbonyl-amine reaction followed by a free radical amino-acid degradation, mainly phenylalanine. It was previously shown that flaxseed is a rich source of 6 essential amino-acids, from which phenylalanine amount could vary in the range from 1.44 mg/100 g up to 66.6 mg/100 g, depending on the flaxseed cultivars [57].