## 2 Results and Discussion
### Phenolic Compounds Profile and Quantification
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Phenolic Compound**}} & \multicolumn{5}{c}{**Bravo de Esmolfe Apple Extracts**} \\ \cline{2-6}  & & **CE** & **CET** & **MAE** & **UAE** \\ \hline \multicolumn{6}{c}{Hydrooxcinnamic Acids} \\ \hline
3 & Chlorogenic Acid & 0.11 \(\pm\) 0.01 \({}^{\text{c}}\) & 0.34 \(\pm\) 0.05 \({}^{\text{b}}\) & 0.48 \(\pm\) 0.07 \({}^{\text{a}}\) & 0.12 \(\pm\) 0.01 \({}^{\text{c}}\) \\
4 & Cryptochlorogenic Acid & 0.05 \(\pm\) 0.00 \({}^{\text{b}}\) & 0.08 \(\pm\) 0.02 \({}^{\text{b}}\) & 0.12 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.05 \(\pm\) 0.01 \({}^{\text{b}}\) \\
2 & p-Counaroylquinic acid & 0.05 \(\pm\) 0.01 \({}^{\text{c}}\) & 0.19 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.18 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.07 \(\pm\) 0.00 \({}^{\text{b}}\) \\
1 & p-Counaric acid & - & 0.10 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.09 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.04 \(\pm\) 0.02 \({}^{\text{a}}\) \\ \hline \multicolumn{6}{c}{Flavanols} \\ \hline
5 & (+)-Catechin & - & 0.19 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.18 \(\pm\) 0.03 \({}^{\text{a}}\) & - \\
6 & (\(-\))-epicatechin & 0.11 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.34 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.30 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.10 \(\pm\) 0.01 \({}^{\text{a}}\) \\
7 & (\(-\))-epicatechin-3-gallate & 0.05 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.10 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.10 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.06 \(\pm\) 0.02 \({}^{\text{a}}\) \\
8 & Procyanidin B2 & - & 0.09 \(\pm\) 0.01 \({}^{\text{b}}\) & 0.11 \(\pm\) 0.01 \({}^{\text{a}}\) & - \\
9 & Procyanidin C1 & - & 0.05 \(\pm\) 0.02 \({}^{\text{b}}\) & 0.12 \(\pm\) 0.01 \({}^{\text{a}}\) & - \\ \hline \multicolumn{6}{c}{Flavonols} \\ \hline
10 & Quercetin-3-rutinoside & - & 0.09 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.10 \(\pm\) 0.01 \({}^{\text{a}}\) & - \\ \hline \multicolumn{6}{c}{Dihydrochalcones} \\ \hline
11 & Phloretin & - & 0.11 \(\pm\) 0.01 \({}^{\text{a}}\) & 0.07 \(\pm\) 0.00 \({}^{\text{b}}\) & - \\
12 & Phlorelin & - & 0.21 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.13 \(\pm\) 0.01 \({}^{\text{b}}\) & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Quantification of main phenolic compounds (mg/g DE) in different extracts of BE apples by HPLC-DAD. Values are represented by the average \(\pm\) standard deviation. Different letters in the row (a, b, c) mean significant differences between extraction techniques, determined by [PERSON]’s test (\(p\) < 0.05). targeted compounds, revealing to be an important parameter that should be taken into consideration for ultrasonic extraction procedures. In a previous work with BE apple from Mangualde region purchased in 2006, eight phenolic compounds were quantified, and chlorogenic acid and (\(-\))-epicatechin were the two most representative compounds with 9.11 \(\pm\) 0.81 and 8.19 \(\pm\) 0.51 mg/100 g fresh apple, respectively [1]. However, despite [PERSON] et al. [4] having observed precisely the same compounds reported in this previous study to BE apple purchased in 2007 also from Mangualde, they observed a higher amount of (\(-\))-epicatechin (12.80 \(\pm\) 0.21 mg/100 g fresh apple) and chlorogenic acid (17.02 \(\pm\) 0.44 mg/100 g fresh apple). On the other hand, [PERSON] et al. [3] observed that chlorogenic acid was the most abundant phenolic compound in hydomethacinic extracts of dried BE apple. Thus, these polyphenols concentrations may depend on many factors, such as plant genotype, maturation stage, climatic conditions, agronomic practices, storage and processing [36; 37; 38; 39; 40]. Therefore, it is necessary take into consideration these factors for future reproducibility in the bioactive extracts production. However, pre-harvest factors optimization may be difficult due to varying environmental conditions and differences in farm management practices [41]. On the other hand, the polyphenols concentration is different in different parts of the plant (pulp, peel, seed, stem).