Table 2.
Specific polyphenols (mean ± SD; n = 3) detected and quantified by HPLC-DAD in water–ethanol extracts (native powder and their micellarized formulations) of apple (M. domestica cv. Anna), plum (P. domestica cv. Satsuma), and guava (P. guajava L.) fruits.
| Compound | Retention Time (min) | UV/Vis Wavelength (nm) | Polyphenol Concentration [ug mg−1 Extract] in Native Extracts | Proportion of Polyphenols in Micelles/Native Extract | |||||
|---|---|---|---|---|---|---|---|---|---|
| Whole Apple | Apple Peel | Plum | Guava | Apple Peel | Plum | Guava | |||
| Gallic acid | 2.0 | 201/220/270 | n.d. | n.d. | 0.81 ± 0.49 a | 2.65 ± 0.10 b | n.d. | 19.29 | 4.97 |
| Catechin | 7.7 | 201/278 | 0.83 ± 0.49 a | 1.27 ± 0.42 a | 9.44 ± 6.87 a | 24.07 ± 0.88 b | n.d. | 2.91 | n.d. |
| Epicatechin | 9.0 | 201/281/324 | 2.68 ± 1.34 a | 2.91 ± 0.36 a | 7.05 ± 1.25 b | 2.26 ± 0.08 a | 2.56 | 1.09 | n.d. |
| Rutin | 11.2 | 201/256/355 | 1.08 ± 0.07 a | 5.54 ± 0.79 b | 5.97 ± 1.21 b | n.d. | 1.14 | 0.45 | n.d. |
| Quercetin | 13.1 | 201/255/370 | n.d. | n.d. | 0.55 ± 0.30 a | 1.09 ± 0.04 b | n.d. | 17.26 | n.d. |
| Phloretin xyloglucoside ti | 11.4 | 191/220/286 | n.c. | n.c. | n.d. | n.d. | 0.94 | n.d. | n.d. |
| Quercetin glucoside ti | 11.6 | 199/257/353 | n.c. | n.c. | n.d. | n.d. | 1.01 | n.d. | n.d. |
| Phloridzin ti | 11.9 | 191/221/286 | n.c. | n.c. | n.d. | n.d. | 1.28 | n.d. | n.d. |
n.d., not detected; n.c., not quantified; and ti, tentatively identified polyphenols based on Tsao et al. [19]. The relative amounts of tentatively identified polyphenols in micelles relative to the native formulation were estimated by comparing the peak area. The other polyphenols were identified based on their concentration as determined by comparison with authentic standards. For polyphenol concentrations, one-way ANOVA followed by Tukey’s multiple comparison tests were carried out within each row. Data within rows that do not share the same superscript letters are significantly different at p < 0.05 (Rstudio 4.1.0., Boston, MA, USA).