## 3 Results and Discussion
### Content of Bioactive Compounds in Seed Powders  
Table 3 shows the total polyphenol, tannin content and antioxidant activity of mango and rampbutan seed powders obtained by convective drying (CD) and sublimation drying (FD). The seed powders obtained by sublimation drying were characterized by a significantly (\(p<0.05\)) higher total polyphenic content and higher antioxidant activity compared to seed powders obtained by convective drying. The powder obtained from sublimation-dried mango seeds was characterized by the highest polyphenol content and the highest antioxidant activity. The content of total polyphenols was about 112 mg GAE/1 g d.m. and its antioxidant potential was about 144 mmol TEAC/100 g d.m. In a study by [PERSON] et al., (2007) [42], similar levels of total polyphenols were obtained in convection-dried mango seed powder, and in the study of [PERSON] and [PERSON] (2004) [4], the powder obtained after sublimation drying of the seed showed similar levels of polyphenols as those in this study for FD powder. The powder obtained from convection-dried seed was characterized by a significantly (\(p<0.05\)) lower polyphenol content (about 43 mg GAE/1 g d.m.) --almost three times that of the powder obtained from freeze-dried seeds--and a lower antioxidant activity equal to 93 mmol TEAC/100 g d.m. Despite using the same assay methods, the study of [PERSON] et al. (2013) [43] obtained higher values than the present work: 172.4 mmol TEAC/100 g d.m. for freeze-dried seeds and 123.3 mmol TEAC/100 g d.m. for convection-dried seeds, respectively. The content of polyphenols in the powder obtained from freeze-dried rambutan seeds was 2.69 mg GAE/1 g d.m., while in the powder from convection-dried seeds, the content of polyphenols was twice lower at 1.18 mg GAE/1 g d.m. In the literature data, the content of these bioactive ingredients ranges from 3.05 mg GAE/1 g d.m. [44] up to 124.14 mg GAE/1 g d.m. [45]. Despite their lower polyphenol content, rampbutan seed powders had a high antioxidant potential. The powder obtained from freeze-dried rambutan seeds had an antioxidant activity at the level of about 67 mmol TEAC per 100 g d.m., while the powder obtained from convection-dried seeds showed a slightly lower antioxidant potential--about 51 mmol TEAC per 100 g d.m. In the available literature, there are few studies on the antioxidant activity of powders from the tested mango and rampbutan seeds. The available data on both the antioxidant potential and the total polyphenol content vary depending on the drying methods used or \begin{table}
\begin{tabular}{c c c c} \hline
**Powders** & **Total Polyphenols** & **Tannins** & **Antioxidant Activity** \\  & **[mg GAE/1 g d.m.]** & **[g/100 g]** & **[mmol Trolox/100 g d.m.]** \\ \hline MSCD & 42.92 \({}^{\text{a}}\)\(\pm\) 0.47 & 0.33 \({}^{\text{a}}\)\(\pm\) 0.12 & 93.40 \({}^{\text{a}}\)\(\pm\) 0.62 \\ MSFD & 111.67 \({}^{\text{b}}\)\(\pm\) 0.29 & 0.49 \({}^{\text{b}}\)\(\pm\) 0.09 & 143.85 \({}^{\text{b}}\)\(\pm\) 0.15 \\ RSCD & 1.18 \({}^{\text{A}}\)\(\pm\) 0.12 & 2.25 \({}^{\text{B}}\)\(\pm\) 0.22 & 50.96 \({}^{\text{A}}\)\(\pm\) 0.14 \\ RSFD & 2.69 \({}^{\text{B}}\)\(\pm\) 0.10 & 1.66 \({}^{\text{A}}\)\(\pm\) 0.10 & 67.60 \({}^{\text{B}}\)\(\pm\) 0.16 \\ \hline \end{tabular}  
* Means in columns with different letters within the same type of powder (\({}^{\text{ab}}\) for mango seed powder, \({}^{\text{A,B}}\) for rampbutan seed powder) differ significantly (\(p<0.05\)); MSCD—conventionally dried mango seed powder; MSFD—freeze-dried mango seed powder; RSCD—conventionally dried rambutan seed powder; RSFD—freeze-dried rambutan seed powder.  
\end{table} 
Table 3: Total polyphenol, tannin content and antioxidant activity of mango and rampbutan seed powders dried by different methods. different analytical methods, including the extraction procedures and extraction solvents used.