## 3 Results
### Characterization of Solid Fractions Obtained after OH and CONV Extraction of Tomato Bagasse
In general, dietary fiber and polyphenols are usually analyzed separately, however, currently, bound polyphenols are included as components of dietary fiber due to their well-documented association with significant contribution of bound polyphenols to the health-related properties attributed to dietary fiber [41]. The industrial puree process eliminates most of the pulp from tomato fruit, resulting in a byproduct composed mainly of peels and seeds. Therefore, since phenolic compounds are covalently bound to cell wall structural components, such as hemicellulose, cellulose, lignin, pectin, and structural proteins, these samples are rich in phenolics in insoluble forms [42]. In addition, other studies with fruits and vegetables indicate that BPC were largely related to IDF [12; 38; 43]. It is important to note that BPC can be released and absorbed in the organism during the digestion process [42]; furthermore, they also contribute to antioxidant activity. As reported before for tomato [38] IDF of tomato flows constitutes a higher source of bound phenolics than SDF (\(p<0.05\)). The SFCONV and SFOH exhibited similar amounts of BPC (31.18-34.10 \(\pm\) 1.21 mg GAE/100 g fiber DW). Concerning SDF, SFOH showed a higher BPC value (7.80 \(\pm\) 0.43 mg GAE/100 g fiber DW) than SFCONV (4.99 \(\pm\) 0.35 g GAE/100 g DW), despite the lowest SDF content of SFOH. Comparing the results, OH extraction seemed to be more efficient on the retention of the bound phenolics associated to fiber than CONV extraction. Similar results were found in the literature with corn flows obtained by traditional nitdamization and ohmic heating process [35]. \begin{table}
\begin{tabular}{l c c c} \hline \hline  & **SFOH** & \multicolumn{2}{c}{**SFCONV**} \\ \hline  & **SDF** & **IDF** & **SDF** & **IDF** \\ \hline Klason Lignin & n.d. & 13.06 \(\pm\) 0.52 b  & n.d. & 14.09 \(\pm\) 0.27 a  \\ Glucose (as & 24.42 \(\pm\) 0.43 a  & 55.32 \(\pm\) 1.21 b  & 32.1 \(\pm\) 0.56 c  & 50.23 \(\pm\) 1.76 d  \\ Hemicellulose & 15.12 \(\pm\) 0.54 a  & 25.2 \(\pm\) 0.10 b  & 12.71 \(\pm\) 1.21 a  & 24.72 \(\pm\) 0.30 b  \\ Xylose & * & 13.2 \(\pm\) 0.10 a  & * & 15.1 \(\pm\) 0.17 b  \\ Galactose & 1.87 \(\pm\) 0.21 & * & * & 0.31 \(\pm\) 0.021  \\ Mannose & * & * & 4.10 \(\pm\) 0.12 a  & * \\ Arabinose & 13.25 \(\pm\) 0.86 & 12.81 \(\pm\) 0.28 & 12.71 \(\pm\) 1.21 & 9.31 \(\pm\) 0.51 \\ Uronic acids* & 67.41 \(\pm\) 2.15 a  & 81.92 \(\pm\) 1.98 b  & 58.93 \(\pm\) 2.56 c  & 78.49 \(\pm\) 2.32 b  \\ Resistant Protein & n.d. & 16.03 \(\pm\) 0.05 a  & n.d. & 11.69 \(\pm\) 0.03 b  \\ Bond Phenolic & 7.80 \(\pm\) 0.43 a  & 31.18 \(\pm\) 2.31 b  & 4.99 \(\pm\) 0.35 c  & 34.10 \(\pm\) 1.21 b  \\ compounds *** & & & & \\ \hline \hline \end{tabular}  
* \(<\) LOD; n.d., nondeterminate; IDF, insoluble dietary fiber; SDF, soluble dietary fiber. **, mg GAE/g fiber DW; ***, mg GAE/100 g fiber DW. Results are the means of three determinations \(\pm\) standard deviation. Different letters in the same row are significantly different, as determined by ANOVA (\(p<0.05\)).  
\end{table} 
Table 2: Constituents (g/100 g fiber DW) of SDF and IDF from SFOH and SFCONV samples. Total Phenolic Compounds, and Individual Compounds throughout the Digestive Tract and Antioxidant Activity  
Although polyphenols are released to the liquid extract, phenolics intimately bound to the fiber are not extracted and remain part of the flour in both SFOH and SFCONV. Thus, bound polyphenols-fiber on both fractions were analyzed to evaluate its potential as antioxidant fiber and its bioaccessibility (Figure 2 and Table 3). The results showed a similar slight increase in total polyphenols content throughout the digestive tract. There is a significant difference between flows (SFOH and SFCONV) (\(p<0.05\)) resulting in more OH extraction efficiency than with the CONV method to liquid fraction preparation. The TPC showed a slight increase in the mouth phase in SFCONV samples (RI 101.42%), while the SFOH decreased significantly (RI 70.44%).