## 3 Results and Discussion  
### Total Soluble Solids Content and Titratable Acidity  
The onset of berry ripening was determined based on TSS and TA. Dramatic changes in the physical, chemical, and physiological properties of grape berries can be observed at veraison. An increase in berry size and volume, accumulation of sugars, tannins, and anthocyanins, and degradation of organic acids and chlorophylls are commonly observed after veraison [19]. Monitoring the changes in TSS and TA in grape berries is an important indicator for judging the end of veraison, representing the onset of ripening [20], especially for white grape cultivars. TSS showed a rapid increase between 6 and 8 WAFB due to the accumulation of sugars and then gently increased during the ripening period, while the change in TA showed the opposite trend. The TSS of the berry extract was 3.8 \({}^{\circ}\)Bx at 6 WAFB, increased to 11.5 \({}^{\circ}\)Bx at 8 WAFB, and then reached a maximum of 20.1 \({}^{\circ}\)Bx at 22 WAFB (Figure 1 and Table 1). On the other hand, the TA was 2.8% at 6 WAFB, decreased to 1.1%, reached approximately 0.3% at 16 WAFB, and remained constant thereafter (Figure 1 and Table 1). The rapid increase in TSS and reduction in TA starting at 6 WAFB visibly indicates the onset of grape berry ripening, as shown in Figure 1.  
The Shine Muscat grape berry surpassed the minimum quality requirement of 16 \({}^{\circ}\)Bx specified by the Codex Standard 255-2007 for table grapes [7] at 16 WAFB as 17.5 \({}^{\circ}\)Bx (Table 1). The Brix/acid ratio of grape berries was very low (1.4) at the beginning of ripening because of the low sugar and high acid content and then reached 20 at 12 WAFB, which is the minimum quality requirement specified by the Codex Standard 255-2007 for table grapes [7]. The Brix/acid ratio rapidly increased with ripening by 16 WAFB due to the accumulation of sugars and degradation of organic acids and plateaued thereafter. The Brix/acid ratio is considered an alternative indicator of \({}^{\circ}\)Bx for determining the ripeness of grapes [21] because of the variation in both sugar and acid levels in grape berries from year to year under the same cultivation conditions. Furthermore, the Brix/acid ratio is more important with respect to consumer acceptance than either \({}^{\circ}\)Bx or acid concentration alone [22]. [PERSON] [2] investigated the effects of the Brix/acid ratio on \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{\({}^{\textbf{1}}\) WAFB} & \multirow{2}{*}{\({}^{\textbf{2}}\) TSS (\({}^{\circ}\)Bx)} & \multirow{2}{*}{\({}^{\textbf{3}}\) TA (\%)} & \multicolumn{2}{c}{**4 PTC**} & \multicolumn{2}{c}{**Textural Properties**} \\ \cline{5-6}  & & & **mgTAE/gDW** & **Skin Rupture** & **Flesh** \\  & & & & **Strength (N)** & **Firmness (N)** \\ \hline
16 & 17.5 \(\pm\) 0.3 \({}^{\text{b}}\) & 0.34 \(\pm\) 0.01 \({}^{\text{a}}\) & 9.1 \(\pm\) 0.3 \({}^{\text{b}}\) & 10.99 \(\pm\) 1.26 \({}^{\text{a}}\) & 2.48 \(\pm\) 0.32 \({}^{\text{a}}\) \\
18 & 17.6 \(\pm\) 0.1 \({}^{\text{b}}\) & 0.37 \(\pm\) 0.02 \({}^{\text{a}}\) & 10.2 \(\pm\) 0.5 \({}^{\text{a}}\) & 6.8 \(\pm\) 1.11 \({}^{\text{b}}\) & 1.73 \(\pm\) 0.14 \({}^{\text{b}}\) \\
20 & 19.6 \(\pm\) 0.3 \({}^{\text{a}}\) & 0.39 \(\pm\) 0.04 \({}^{\text{a}}\) & 10.0 \(\pm\) 0.4 \({}^{\text{a}}\) & 5.99 \(\pm\) 0.83 \({}^{\text{b}}\) & 1.82 \(\pm\) 0.25 \({}^{\text{b}}\) \\
22 & 20.1 \(\pm\) 0.3 \({}^{\text{a}}\) & 0.33 \(\pm\) 0.02 \({}^{\text{a}}\) & 10.1 \(\pm\) 0.4 \({}^{\text{a}}\) & 6.14 \(\pm\) 0.39 \({}^{\text{b}}\) & 1.99 \(\pm\) 0.12 \({}^{\text{b}}\) \\ \hline \hline \end{tabular}  
\({}^{\textbf{1}}\) WAFB: Weeks after full bloom; \({}^{\text{2}}\) TSS: Total soluble solid content; \({}^{\text{3}}\) TA: Titractable acidity; \({}^{\text{4}}\) PTC: Polymeric tannin content expressed in tannic acid equivalent. Different letters (a and b) within the same column indicate significant differences at \(p<0.05\).  
\end{table}