## 3 Results and Discussion
### Effect of Illumination on FTIR Spectra  
The FTIR spectra of the three chia samples under the study are depicted in Figure 5, and their main bands are summarized in Table 2. It can be observed that they are similar, in particular, the samples exposed to light for 24 and 48 h.  
A large number of peaks appeared in the region from 1000 to 3000 cm\({}^{-1}\), indicating that chia microgreens have a rich chemical composition (proteins, lipids, carbohydrates) [18]. More precisely, the band located around 3290 cm\({}^{-1}\) represents N-H stretching vibrations that are caused by proteins [20]. The bands between 2800 and 3000 cm\({}^{-1}\) mainly represent C-H stretching vibrations that are caused by lipids. The region between 1550 and 1700 cm\({}^{-1}\) are protein absorption bands, including amide I and  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Peak No.** & **Assignments** & \begin{tabular}{c} **Dark-Grown** \\ **Wavenumber (cm\({}^{-1}\))** \\ \end{tabular} & \
\begin{tabular}{c} **24 h** \\ **Wavenumber (cm\({}^{-1}\))** \\ \end{tabular} &
\begin{tabular}{c} **48 h** \\ **Wavenumber (cm\({}^{-1}\))** \\ \end{tabular} \\ \hline I & not assigned & 889.9 & 890 & 889 \\ II & Polysaccharides & 1062 & 1062 & 1063 \\ III & Amide III region & 1238 & 1239 & 1239 \\ IV & Amide III region & 1457 & 1457 & 1457 \\ V & Amide II region & 1540 & 1540 & 1540 \\ VI & Amide I region & 1647 & 1647 & 1647 \\ VII & Fat content & 2855 & disappeared & disappeared \\ VIII & Fat content & 2926 & 2927 & 2925 \\ IX & Protein content & 3269 & 3270 & 3271 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Main bands in the FTIR spectra and their assignments of dark-grown chia microgreens and microgreens after exposure to light for 24 and 48 h.  
Figure 5: FTIR spectra of dark-grown (**a**) chia microgreens and microgreens after exposure to light for 24 (**b**) and 48 (**c**) h. FTIR spectrum was recorded by 20 co-added scans at a resolution of 2 cm\({}^{-1}\) in the region of wave number (WN) 500 to 4000 cm\({}^{-1}\). The spectra were baseline-corrected.  
amide II. Additionally, the fingerprint region between 1000 and 1500 cm\({}^{-1}\) is where amide II and the functional groups of nucleic acid and carbohydrates contribute to these absorption bands.  
In comparison with the other two samples, the dark-grown chia sample showed negligible differences regarding the peak shifting in the region comprised between 1000 and 1700 cm\({}^{-1}\). We observed two well-pronounced bands in dark-grown chia microgreens around 2855 and 2926 cm\({}^{-1}\). Regarding the peak shifting, with the increment of light treatment, the band at about 2855 cm\({}^{-1}\) (dark-grown microgreens) disappeared in illuminated microgreens (24 and 48 h), while bands at 2926 cm\({}^{-1}\) remain relatively stable in all chia samples.  
Nine main bands were analyzed between 800 and 3500 cm\({}^{-1}\) in the spectra of the three chia samples, and the band positions were relatively similar (with the exception of the band at 2855 cm\({}^{-1}\)) to each other, indicating that structure was sensitive to treatments in the region of fats, vax, and lipids after 24 and 48 h of exposure to light [19; 20].