# Carrot Pomace Characterization for Application in Cereal-Based Products
## 4 Discussion
[19] reported the intact cellular structure of black carrots that could be related to the filled polymer network and also to the strong linkages of pectin molecules with the pigments. Plant cell walls are formed of complex polysaccharide networks with diverse structural and physiological importance, with pectins being the components that, together with other polysaccharides paste neighboring cells and strengthen them firmly [33]. The main components of the carrot cell wall are represented by pectin (galacturonans, rhamnagalacturonans, arabinans, galactans, and arabininogalactans-1), cellulose (\(\beta\)-4, D-glucan), lignin (trans-coniferyl alcohol, trans-sinaryl alcohol, and trans-p-coumaryl alcohol), and hemicellulose (xylans, glucuronoxylans \(\beta\)-D-glucans, and xyloglucans) [1]. A comparison of FT-IR absorption bands between the results obtained in the present study and those found in the literature are listed in Table 4. The peak at 1736 cm\({}^{-1}\) due to C=O stretching can be led to the bonds present in \(\beta\)-carotene [34]. The peak at 1456 cm\({}^{-1}\) is related to scissoring (CH\({}_{2}\)) bending, while the peaks found at 1421 cm\({}^{-1}\) and 1367 cm\({}^{-1}\) are assigned to (CH\({}_{3}\)) and (CH\({}_{2}\)) bending, respectively. [20]. The bands observed between 1550-1650 cm\({}^{-1}\) in FT-IR spectrum of carrot pomace (Figure 2b) are the indicators of the C=C stretches in the pectin fractions [21]. The presence of the -OH groups of water was identified between 3000 and 3600 cm\({}^{-1}\) as a broad band. The peaks at 3324 cm\({}^{-1}\) given by the -OH stretching vibrations also led to the H-bonded hydroxyl of polysaccharides or polyphenols [19]. The peaks at around 2898 and 1606 cm\({}^{-1}\) can be associated with the -CH stretching vibrations and the appearance of free ionic non-esterified carboxyl (-COO) molecules of galacturonic acid [19]. The presence of cellulose in carrot pomace powders was suggested by the absorption bands found at 1421, 1367, 1104, and 1032 cm\({}^{-1}\)[22]. The peaks at 1649 and 1557 cm\({}^{-1}\) given by the C-O, C-N, CNN (Amide I), and N-H, C-N (Amide II) [35] vibrations, respectively, can be related to the presence of proteins in the studied samples. These results were in agreement with those obtained for the chemical composition of carrot pomace powders which showed high content of fibers and important amounts of proteins. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Measured** & **Wavenumber from the Literature** & & \\
**(cm\({}^{-1}\))** & **(cm\({}^{-1}\))** & & \\ \hline
3324 & 3000–3600 & O–H and N–H stretch C–H & Water, alcohols, phenols, carbohydrates, peroxides polysaccharides, lipids, and carbohydrates \\
2898 & 2891 & –CH stretching vibrations & Galacturonic acid \\
1717, 1736 & 1700–1799 & C=O & Lipids, beta caroten \\  & & Amide I of proteins, C–O, & Proteins \\
1649 & 1600–1706 & C=N, CNN & \\  & & COO- & Polygalacturonic acid, carboxylate \\
1606 & 1600–1630 & antisymmetric stretching & (pectin ester group) \\  & & Amide II of proteins, N–H, & Proteins \\
1557 & 1460–1590 & C=N & \\  & & CH\({}_{3}\) symmetric bending & Cellulose \\
1421 & 1421–1428 & CH\({}_{2}\) bending & Xyloglucan, Cellulose \\
1367 & 1370 & CH\({}_{2}\) bending & Cycloglucan, Cellulose \\
1329 & 1320–1330 & Ring vibration & Pectin \\
1247 & 1243 & C–O stretching & Pectin \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of FT-IR absorption bands with previous results reported in the literature [19; 22; 35]. The results obtained in the present study confirm the possibility of using carrot pomace in the production of value-added food, with low costs and with many benefits for consumer health. Some possible applications of carrot pomace powders would be wheat bread, gluten-free bread based on pseudo-cereals, fitness bars, biscuits, cakes, pasta, etc. Carrot pomace could bring an important intake of nutrients, especially fibers, depending on the amount added to the final product.