# The Effect of Processing Methods on Phytochemical Composition in Bergamot Juice
## 3 Results
### Phytochemical Content in Bergamot Juices Obtained with Different Juice Extraction Systems  
BJ was characterized by noticeable amounts of flavanone-7-O-neohesperidosides (naringin, neoeriocitrin, and neohesperidin) and lower amounts of flavanone-7-O-rutinosides (narirutin). The typical flavanone glycosides pattern of bergamot juice was shown in Figure 2 (panels b-d). The detection limits (LOD) found using RP-HPLC-DAD analysis were 0.5 mg/L, while the calculated limits of quantification (LOQ) were 1 mg/L for each flavanone glycosides. The validation process of HPLC analysis showed a good resolution of all components (Figure 2a), excellent linearity, as confirmed by the correlation coefficient \(R^{2}\), ranging from 0.990 to 0.998, and a good precision, at the concentration level tested, since the coefficient of variation (CV) values were \(<\)5% for all the analytes. Considering the involvement of procedures as extraction, filtration and dilution of sample, the precision and the accuracy of the analytical method were acceptable with intra/inter assay coefficient of variation below 2.3% and 3.9%. Results reported in Table 2 and Figure 2 suggested that BJ obtained by screw press (Ep-3) had significantly (\(p<0.001\)) higher levels of flavanone glycosides (neoeriocitrin, naringin, neohesperidin) compared to hand squeezed juices (Ep-1) and BJ processed by and FMC (Ep-2). No significant variation in flavanone glycosides content was noticed in the hand squeezed juices and BJ obtained by Ep-2 (\(p<0.1\)). Naringin was the most abundant flavonoid present (\(394\pm 83\); \(175\pm 58\); and \(97\pm 13\) mg/L in Ep-3, Ep-2, and Ep-1, respectively). The content of neoeriocitrin ranged from \(114\pm 20\) mg/L in Ep-1 juice to \(402\pm 122\) mg/L in Ep-3 juice, while the concentration of neohesperidin was found to be about 1.5- to 1.7-fold lower than naringin content. \begin{table}
\begin{tabular}{c c c c} \hline  & **Ep-1** & **Ep-2** & **Ep-3** \\ \hline Total soluble solids (\%) & \(9.5\pm 0.4\)  & \(9.1\pm 1.2\)  & \(42.5\pm 3.5\)  \\ L-ascorbic acid (mg/L) & \(421\pm 25\)  & \(416\pm 33\)  & \(640\pm 43\)  \\ Water-soluble pectins (mg/L) & \(278\pm 37\)  & \(473\pm 81\)  & \(16.8\pm 4.5\)  \\ Glucose (g/L) & \(13.1\pm 1.5\)  & \(12.2\pm 1.9\)  \\ \hline \end{tabular}
\end{table} 
Table 1: Proximate constituents (mean \(\pm\) standard deviation, \(n=3\)) of bergamot juice obtained using 3 different extraction methods: hand squeezing (Ep-1); FMC (Ep-2); screw press of peeled fruits (Ep-3). Data from Table 2 showed that \(N_{N}\)/\(N\)-dimethyl-\(L\)-proline was the main proline derived osmoprotectant compounds present in BJ. The process used for extraction of BJ did not affect significantly the \(N_{N}\)/\(N\)-dimethyl-\(L\)-proline content in juice (\(p<0.\) 5). As reported in Table 2, the content of limonoid aglycones, limonin, and nomilin, increased significantly in the screw press (Ep-3) BJ with an average content of 65 mg/L. BJ obtained by FMC (Ep-2) did not significantly differ from hand squeezed (Ep-1) juice as regarding the limonin content (\(p<0.05\)), while nomilin appeared to be lower in the Ep-1 juice. Since bitterness in BJ was primarily related to two classes of compounds: neohesperidose O-flavanone glycosides (neoeriocitrin, naringin, and neohesperidin) and limonoids (limonin, nomilin), the content of these compound was evaluated in BJ treated with polystyrene-DVB resins (Amberlite XAD-16) batch process. In Table 2 the content of flavanone glycosides and limonoid aglycones of debittered BJ samples was also reported. The effect of resin treatment significantly reduced (\(p<0.001\)) the amount of the flavanone glycosides, limonin, and nomilin (Figure 2, Table 2), but seemed to not