## 3 Results and Discussion
### Phenolic Profiles of the Extracts  
The examples of the sample phenolic profiles are reported in Figure 3. Table 4 reports the phenolic profiles of the extracts obtained for each technique under the conditions that allowed to maximize the relative TPCs. LOD and LOQ were calculated for each phenolic compound, with the first ranging from 0.11 to 0.32 mg/L and the latter ranging between 0.45 and 0.95 mg/L. Regarding chicory by-products: 14 peaks were identified in conventional extracts, with epigallocatechin, rutin, sinapic acid and epicatechin occurring in higher concentrations; 17 compounds were identified in UAE extracts, with rosmarinic, sinapic, and chlorogenic acid as the most representative phenolics; the MAE extracts showed the simpler profile with only eight peaks, and epicatechin and rosmarinic acid as the main phenolics. With respect to the other extraction system, the conventional system allowed the extraction of more 4-hydroxybenzoic, \(p\)-coumaric and vanillic acids, as well as rutin, catechin, and epigallocatechin. UAE was more effective in the extraction of gallic, rosmarinic, sinapic and chlorogenic acids, as well as quercetin and epigallocatechingallate. No compound was extracted to a greater extent through the application of MAE. Figure 3: Phenolic profiles acquired at 280 nm, of (**a**) chicory and (**b**) funnel extracts obtained by applying UAE under the conditions that allowed the maximization of the relative TPCs. 1: Gallic acid; 2: 4-Hydroxybenzoic acid; 3: Catechin, 4: Vanillic acid; 5: Caffeic acid; 6: Syringic acid; 7: Epicatechin; 8: Chlorogenic acid; 9: Epigallocatechin; 10: Ferulic acid; 11: \(p\)-Coumaric acid; 12: Sinapic acid; 13: Epicatechingallate; 14: Rutin; 15: Resveratrol; 16: Rosmarinic acid; 17: Quercetin; 18: Kaempfer. Concerning fennel by-products, nine compounds were identified in conventional extracts, with sinapic acid and epigallocatechingallate present in higher concentrations; 11 peaks were identified in extracts obtained through ultrasounds, with epicatechin being the most representative phenolic compound; 14 compounds were recognized in MAE extracts, with epicatechin present in the highest concentrations. Compared to the other extraction techniques, the conventional system allowed a greater extraction of vanillic and sinapic acids, as well as epigallocatechingallate, while MAE was more able to extract catechin, epicatechin, epigallocatechin and kaempfer. Ferulic and caffe acids were better extracted by both UAE and MAE. Independent of the extraction method, the aqueous extracts of chicory and fennel by-products are confirmed as an easily available source of dietary polyphenols [42]. As can be inferred from these data, the highest number of compounds was recognized in UAE, followed by conventional extracts and MAE extracts. In more depth, the extraction techniques influenced not only the extraction yield but also the number, type and concentrations of the individual phenolic compounds, and the effects depended on the matrices. These results are in agreement with those of [PERSON] et al., who highlighted that each extraction technique among those that they decided to apply to _Moringa oleifera_ leaves (maceration, homogenizer-assisted extraction, solid/liquid dynamic extraction, microwave-assisted extraction and ultrasound-assisted extraction) promoted the recovery of specific phenolic subclasses with different efficiencies [43]. These findings are also related to the separation properties of phenolic compounds, which are in turn affected by their structural characteristics. It is known that the structures of polyphenols influence their polarity, conjugation and interaction with the sample matrix, and in turn their propensity to be extracted with a particular extraction procedure since each extraction technique is based on peculiar operating principles. According to a review of [PERSON] et al.