## 3 Results and Discussion
### pH and Total Titractable Acidity (TTA)  
Table 5 presents the data on pH and total tittatable acidity (TTA). In most cases, the pH values were higher in the PY samples, whereas the total acidity was higher in the PY samples. This result is consistent with previous findings [37]. Because JY retains the natural composition of the fruit, including organic acids, the total acidity is higher, and the pH is relatively low. In contrast, in the PY samples, the freeze-drying process may have led to the loss of organic acids, resulting in higher pH and lower total acidity. The JG and JK samples exhibited a distinct pattern of pH reduction in response to increasing concentrations, showing the most significant acidification among all the tested samples.  
Grape juice naturally contains various organic acids, such as tartaric acid, malic acid, and citric acid, which contribute to lowering the pH of the product. However, in freeze-dried grape powder, some of these acids may be lost (e.g., volatilized or degraded) during the drying process, increasing the pH. In addition, there are differences in the organic acid composition depending on the grape variety; however, it was confirmed that there was no significant difference in the organic acid composition when Shine Muscat was used to make Yanggaeng [38].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample (1)** & **Soluble Solids** & **Brix (\%)** & **MC (\%)** \\ \hline JG 8\% & 4.85 \(\pm\) 0.14 b  & 4.75 \(\pm\) 0.01 b  & 49.38 \(\pm\) 0.85 cdef  \\ JK 2\% & 4.77 \(\pm\) 0.11 b  & 4.75 \(\pm\) 0.02 b  & 53.87 \(\pm\) 2.65 a  \\ JK 4\% & 4.42 \(\pm\) 0.17 b  & 4.62 \(\pm\) 0.01 d  & 48.19 \(\pm\) 0.94 e  \\ JK 8\% & 4.82 \(\pm\) 0.15 b  & 4.41 \(\pm\) 0.01 e  & 45.79 \(\pm\) 0.27 e  \\ JS 2\% & 4.75 \(\pm\) 0.06 b  & 4.63 \(\pm\) 0.01 cd  & 49.72 \(\pm\) 1.3 b  \\ JS 4\% & 4.56 \(\pm\) 0.12 c  & 4.47 \(\pm\) 0.03 e  & 49.46 \(\pm\) 1.46 c [FONOTE:c]Footnote e: footnotemark: [ENDFOOTNOTE] \\ JS 8\% & 4.33 \(\pm\) 0.08 e  & 4.12 \(\pm\) 0.10 gh  & 44.74 \(\pm\) 0.8 8  \\ \hline \hline \end{tabular}  
* BY: control, PG: Powder Campbell Early, PK: Powder Syroho, PS: Powder Shine Muscat, JG: Jnice Campbell Early, JK: Juice Kyoho, JS: Juice Shine Muscat. All samples contained either 2, 4, or 8% grape powder or juice. \(\alpha\)*-h Different superscripts within the same column differed significantly using [PERSON]’s honest significant difference (HSD) test at \(p<0.05\). All values are mean \(\pm\) SD (\(n=3\)).  
\end{table}
Table 4: _Cont._  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Sample (1)** & **pH** & **TTA** \\ \hline BY & 6.74 \(\pm\) 0.02 (2)ab  & 0.13 \(\pm\) 0.00 f  \\ \hline PG 2\% & 6.91 \(\pm\) 0.09 a  & 0.13 \(\pm\) 0.00 f  \\ PG 4\% & 6.69 \(\pm\) 0.24 ab  & 0.13 \(\pm\) 0.00 f  \\ PG 8\% & 5.9 \(\pm\) 0.12 d  & 0.19 \(\pm\) 0.00 def  \\ PK 2\% & 6.62 \(\pm\) 0.1 ab  & 0.13 \(\pm\) 0.00 f  \\ PK 4\% & 6.52 \(\pm\) 0.25 ab  & 0.13 \(\pm\) 0.00 f  \\ PK 8\% & 6.08 \(\pm\) 0.07 cd  & 0.26 \(\pm\) 0.00 bed  \\ PS 2\% & 6.78 \(\pm\) 0.12 ab  & 0.15 \(\pm\) 0.04 ef  \\ PS 4\% & 6.62 \(\pm\) 0.16 ab  & 0.19 \(\pm\) 0.00 def  \\ PS 8\% & 6.66 \(\pm\) 0.15 ab  & 0.21 \(\pm\) 0.04 c  \\ \hline \hline \end{tabular}
\end{table}
Table 5: pH and total acidity of Yanggaeng with added grape powder or juice.  
Significant differences were observed across the 2, 4, and 8% addition levels, with the most pronounced changes observed in the 8% group. Therefore, subsequent analyses were conducted using only the Yanggaeng samples with 8% grape content.