## 3 Results and Discussion
### Some Chemical and Phytochemical Components  
The total phenolic content (TPC) (mg GAE/100 g) and the antioxidant activity according to ORAC (\(\mu\)mol TE/g) and HORAC (\(\mu\)mol GAE/g) of algae _A. platensis_ (convection dried and lyophilized), _U. intestinalis_, _C. Iinum_, _E. crinita_, and _Chlorella_ spp. (lyophilized samples) were determined (Table 5). The total phenol content in the tested samples was found to be between 2662.4 mg/100 g and 267.7 mg/100 g (Table 5). Brown algae (_E. crinita_) had the highest values for antioxidant activity and polyphenic content. With _Chlorella_ spp., the values of the studied indicators were almost ten times lower. Despite their relatively high polyphenol content, _U. intestinalis_ showed lower antioxidant activity compared to _C. Iinum_ according to HORAC. Lyophilization of _A platensis_ gave statistically indistinguishable values of polyphen content and antioxidant activity compared to conventional drying. The data for polyphen content and antioxidant activity obtained through lyophilization of _A. platentis_ were statistically insignificant compared to conventional drying techniques. The values for the antioxidant activity by the ORAC method were 4 to 5 times higher than those specified by HORAC. The antioxidant activity of _A. platensis_ by the ORAC method was 42% higher than _Chlorella_ spp. extract. In both cases, the values of the antioxidant activity were highest in brown macroalgae _E. crinita_. A correlation was found between the antioxidant capacity and the phenolic content of the studied algae species (marine and freshwater). The coefficient of correlation is high, and the results are presented in Table 6. A similar correlation between antioxidant activity and phenolic content of macroalgae was published by [PERSON], although there are few studies on the relationship between these two algae parameters [71]. Similar results were obtained by [PERSON] et al. [72] in a study of antioxidant activity, total phenolic and flavonoid contents of methanolic extracts of four species of green macroalgae: _Ulva clathrata_, _Ulva lizza_, _Ulva flexuosa_ and _U. intestinalis_ from different parts of the northern shores of the Persian Gulf and south of Iran. The species _Ulva clathrata_ showed the highest activity, as well as the highest total phenolic and flavonoid content. \begin{table}
\begin{tabular}{c c} \hline \hline
**Regression Model** & **Correlation Coefficient** \\ \hline ORAC = 0.1651.TPC + 24.357 & 0.993 \\ HORAC = 0.0422.TPC + 0.7389 & 0.990 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Correlation between total phenolic content and antioxidant activity. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Algae**} & **TPC,** & **ORAC,** & **HORAC,** \\  & **mg GAE/100 g** & \(\mu\)mol TE/g** & \(\mu\)mol GAE/g \\ \cline{2-4}  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** \\ \hline _A. platensis_ & & & \\ (_convection dried_) & & & \\ _A. platensis_ & & & \\ (_lyophilized_) & & & \\ _U. intestinalis_ & & & \\ (_lyophilized_) & & & \\ _C. Iinum_ & & & \\ (_lyophilized_) & & & \\ _E. crinita_ & & & \\ (_lyophilized_) & & & \\ _Chlorella_ spp. & & & \\ (_lyophilized_) & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Total phenolic content (mg GAE/100 g) and antioxidant activity of algae according to ORAC (\(\mu\)mol TE/g) and HORAC (\(\mu\)mol GAE/g). Rutin is a phytochemicalen_E. crinita_ had the highest content of quercetin, catechin, and epicatechin (Figure 3). Quercetin-3-\(\beta\)-glycoside and catechin were not detected in _U. intestinalis_, but it possessed the highest levels of myricetin (30.82 mg/100 g) compared to other species examined. _E. crinita_ did not contain myricetin. Catechin and epicatechin were not detected in both _A. platensis_ samples. The lyophilization process of _A. platensis_ did not affect the content of quercetin but led to a decrease in the values of quercetin-3-\(\beta\)-glycoside, kaempferol,arginine, and naringenin of nearly three times (Figure 3).