# Physicochemical Properties and Sensory Attributes of Yanggaeng Treated with Citrus Peel Powder
## 3 Results and Discussion
### Antioxidative Properties of Yanggaeng  
Table 3 depicts the outcomes of total phenolic (TPC) and flavonoid content (TFC) analysis in Yanggaeng containing CP. In a peer-reviewed study by [PERSON] et al., the analysis of phenolic chemicals in three different types of citrus peels revealed TPC values ranging from 23.14 to 36.22 mg gallic acid equivalent (GAE)/g and TPC values ranging from 12.29 to 24.90 mg quercetin equivalent (QE)/g [31]. In our study, we observed that the TPC of Yanggaeng significantly increased after CP treatment compared to that in CON (\(p<0.05\)). Among the CP-containing Yanggaeng groups, CP6 resulted in a 1.12-fold increase in polyphenol content compared to that in the CON. TFC exhibited a trend similar to that of TPC following CP treatment. Flavonoid contents increased by 5.07-fold, 10.53-fold, and 14.40-fold in the CP2, CP4, and CP6 groups, respectively, compared to CON (\(p<0.001\)). These findings can be linked to the elevated concentrations of flavonoids, such as naringin, hesperetin, rutin, deosmin, and tanveretin, present in citrus peel [31; 32].  
Table 4 indicates the results of the free radical scavenging rates as well as the FRAP of Yanggaeng. In a previous study, CP-treated jelly had elevated levels of both TPC and TFC, as well as DPPH and ABTS free radical scavenging rates, indicating substantial antioxidant activity [33]. Similarly, in this study, the DPPH free radical scavenging rate was lowest in CON (20.01%). However, Yanggaeng prepared with CP2, CP4, and CP6 had a significantly increased DPPH free radical scavenging rate, by 1.27-fold, 1.34-fold, and 1.66-fold, respectively (\(p<0.05\)). ABTS free radical scavenging rates were also the lowest in CON (18.70%), but progressively increased with the addition of CP. ABTS free radical scavenging rates were elevated 1.29-fold, 1.44-fold, and 1.69-fold in the CP2, CP4, and CP6 groups, respectively (\(p<0.0001\)). The FRAP values exhibited a dose-dependent response to increasing CP content in Yanggaeng, mirroring the trend observed for the ABTS free radical scavenging rates. FRAP values were the lowest in CON (3.75 mM FeSO\({}_{4}\)), but steadily and significantly increased with higher CP addition. The FRAP values increased 7.77-fold, 22.53-fold, and 40.87-fold in the CP2, CP4, and CP6 groups, respectively. In this study, a robust positive correlation was observed in the ABTS radical scavenging ability, FRAP, TFC, and TPC. Therefore, the antioxidant activity of Yanggaeng containing CP was likely attributable to the presence of TFC and TPC.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{4}{c}{**Treatments (\%)**} \\ \cline{2-5}  & **CON 1**  & **CP2** & **CP4** & **CP6** \\ \hline Moisture & 49.42 \(\pm\) 0.32 2  & 46.33 \(\pm\) 0.81 2 2  & 48.30 \(\pm\) 0.51 2  & 48.59 \(\pm\) 0.37 2  \\ Crude ash & 0.35 \(\pm\) 0.04 2 2  & 0.34 \(\pm\) 0.05 2 2  & 0.35 \(\pm\) 0.05 2 2  & 0.39 \(\pm\) 0.08 2 2  \\ Crude fat & 0.13 \(\pm\) 0.02 2  & 0.12 \(\pm\) 0.01 2  & 0.14 \(\pm\) 0.00 2 2  \\ Crude protein & 0.05 \(\pm\) 0.01 2 2  & 0.05 \(\pm\) 0.01 2  & 0.16 \(\pm\) 0.01 2  & 0.06 \(\pm\) 0.00 2 2  \\ Carbohydrate 2  & 50.05 \(\pm\) 0.28 2  & 51.15 \(\pm\) 0.55 2  & 50.78 \(\pm\) 0.46 2  \\ \hline \hline \end{tabular}
\end{table}
Table 3: Total phenolic content and total flavonoid content of Yanggaeng made with citrus peel powder.