# Carrot Pomace Characterization for Application in Cereal-Based Products
## 4 Discussion
The porous matrix composed of polysaccharide chains in plants holds high amounts of water by means of hydrogen bonds, thereby offering beneficial functionality to vegetal materials [25]. The main factors influencing the functionality of these polysaccharide chains are the proportion of insoluble to soluble dietary fiber and the dimension of product fraction [27]. Carrots are an important source of soluble fibers such as pectin, which have a higher WRC than insoluble fibers, and could explain the high WRC in carrot fibers. The dietary fiber content of coconut by-products after extraction of coconut milk was reported as being 60.21%, which was higher than that of the carrot pomace powders in the present study (20.09-33.34%), but was comparable with those reported for orange by-product (20.01%) [16]. However, WRC of coconut pomace (5.4 g/g) was close to those obtained in the present study (4.76-7.64 g/g, Table 2) according to the data presented by [PERSON] et al. [16]. The WRC of coconut pomace was greater than that of other dietary fiber wastes such as potato, pea, and wheat bran fibers [16]. These results suggest that the carrot pomace could provide benefits similar to those of coconut pomace, which would be superior to potato, pea, or wheat bran fiber. Carrot pomace OAC was comprised between 34.33% and 37.31% with small differences among varieties. The OAC depends on many factors such as plant polysaccharides, density, hydrophobic particle character, particle size, and the amount of insoluble dietary fiber [25]. Fibers present in carrot pomace could have the ability to stabilize food emulsions with a great fat content [24], which supports the results of the present study. SC is defined as \"the ratio of the volume occupied when the sample is immersed in excess water after reaching equilibrium to the initial sample weight\" [16; 24]. A sample with high SC can be beneficial for gastrointestinal motility and defecation and contribute to the prevention of constipation. Carrot pomace powders presented relatively low foaming capacities (<7%, Table 2) but with good stability. FC and FS are due to the presence of proteins, which form an uninterrupted cohesive film around the air cells in the foam, reducing the surface tension at the air-water interface, therefore providing the foaming capacity [28]. [PERSON] and [PERSON] [29] also reported low FC for apple pomace powder (2%) while [PERSON] et al. [30] obtained a value of 7% FC for unsieved apple pomace and 11.00% for particle size < 300 \(\mu\)m. The bulk densities of carrot pomace powders varied between 0.45 g/cm\({}^{3}\) and 0.56 g/cm\({}^{3}\) (Table 2) with these values being close to those reported by [PERSON] et al. [31] for blackcurrant pomace powders (0.45-0.42 g/cm\({}^{3}\)). Particle density is affected mostly by the solids content which is quite great in fruit by-products such as pomace [31]. The color of carrot pomace is mainly due to carotenes which are partly transformed into vitamin A [8]. [PERSON] et al. [3] reported values of 65.0 for \(L^{*}\), 8.6 for \(a^{*}\), and 20.6 for \(b^{*}\) parameters for carrot pomace convective dried and without any pretreatment, which was close to the results of the present study (Table 3). The color of carrot roots depends on the variety and ranges from orange to purple, depending on the chemical compounds contained [32]. For example, purple carrot color is mainly due to the presence of anthocyanins, while orange color varieties is due to the presence of carotenoids [32]. Niagara carrot pomace powder exhibited the highest color intensity which may be related to the beta caroten content, a fact also supported by the FT-IR spectra which revealed the high est intensity of the peak at 1736 cm\({}^{-1}\) associated with this compound. Generally, food carotenoids are classified into carotenes and xanthophylls, which are responsible for the red or yellow color of the product [1]. The microstructures of carrot pomaces studied in this paper showed compact fibrous structures. [PERSON] et al.