## 2 Results and Discussion  
### Physicochemical Parameters of Goji Wine  
Alcohol strength, volatile acidity, titratable acidity, residual sugar, polysaccharide, free SO\({}_{2}\), total SO\({}_{2}\), and pH of these goji berry fruit wines are listed in Table 1. These goji berry fruit wines contained the high level of the titratable acidity and the pH value, indicating that these wines exhibited a stronger buffer capacity. This wine feature might be attributed to that goji berry is cultivated in a high saline level soil condition.  
Additionally, polysaccharide is an important bioactive component that is largely present in goji berry [15]. The level of polysaccharide in these goji berry wines ranged of 1-3 g/L, which was much higher than that in grape wines (0.2-1.5 g/L) [16]. Meanwhile, the dried goji berry wine made from pressed juice showed the polysaccharide content about 2 times higher than the other goji berry wines, whereas the fresh goji berry pressed juice wine did not show any increase on the level of polysaccharide. These indicated that the drying process of goji berry fruit might cause the structure change of goji berry fruit or polysaccharide in fruit, which resulted in such differences on the polysaccharide level in the wines.  
\begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline
**Oenological Parameters** & **DF** & **DF-G** & **DP** & **DP-G** & **FF** & **FF-G** & **FP** & **FP-G** \\ \hline
**Alcohol (\%, \(\
u\)/o)** & 13.0 \(\pm\) 0.0 a & 13.00 \(\pm\) 0.0 a & 12.5 \(\pm\) 0.2 bcd & 12.6 \(\pm\) 0.0 bc & 12.4 \(\pm\) 0.1 cd & 12.7 \(\pm\) 0.0 b & 12.4 \(\pm\) 0.0 d & 12.3 \(\pm\) 0.0 d \\
**Volatile acidity (g/L)** & 12.2 \(\pm\) 0.0 b & 12.2 \(\pm\) 0.0 bc & 11.1 \(\pm\) 0.0 e & 0.8 \(\pm\) 0.0 g & 12.2 \(\pm\) 0.0 d & 1.0 \(\pm\) 0.6 f & 1.1 \(\pm\) 0.0 de & 2.1 \(\pm\) 0.0 a \\
**Trixtable acidity (g/L)** & 12.2 \(\pm\) 0.1 ab & 11.9 \(\pm\) 0.1 bc & 11.8 \(\pm\) 0.0 c & 12.4 \(\pm\) 0.1 d & 7.9 \(\pm\) 0.0 e & 7.7 \(\pm\) 0.0 e & 8.2 \(\pm\) 0.1 e & 7.8 \(\pm\) 0.0 d \\
**Residual sugar (g/L)** & 9.3 \(\pm\) 0.4 a & 10.0 \(\pm\) 0.4 a & 10.1 \(\pm\) 0.7 a & 9.1 \(\pm\) 0.0 a & 7.8 \(\pm\) 0.1 b & 6.6 \(\pm\) 0.0 b & 8.4 \(\pm\) 0.1 b & 7.6 \(\pm\) 0.1 b \\
**Polysaccharide (g/L)** & 1.6 \(\pm\) 0.1 b & 1.5 \(\pm\) 0.0 bc & 3.0 \(\pm\) 0.1a & 2.9 \(\pm\) 0.1 a & 1.4 \(\pm\) 0.0 d & 1.2 \(\pm\) 0.0 d & 1.3 \(\pm\) 0.1 d & 1.1 \(\pm\) 0.1 f \\ Free \(\mathbf{SO_{2}}\) (mg/L)** & 3.4 \(\pm\) 0.0 c & 1.7 \(\pm\) 0.1 d & 3.4 \(\pm\) 0.0 c & 1.7 \(\pm\) 0.0 d & 13.4 \(\pm\) 0.0 a & 7.3 \(\pm\) 0.4 b & 13.4 \(\pm\) 0.0 a & 6.7 \(\pm\) 0.0 b \\
**Total SO\({}_{2}\) (mg/L)** & 100.0 \(\pm\) 0.1 f & 98.8 \(\pm\) 0.2 g & 93.7 \(\pm\) 0.0 h & 132.1 \(\pm\) 0.0 d & 210.5 \(\pm\) 0.2 b & 155.9 \(\pm\) 0.1 c & 23.7 \(\pm\) 0.1 a & 112.0 \(\pm\) 0.0 e \\ pH & 4.0 \(\pm\) 0.0 c & 3.9 \(\pm\) 0.0 c & 4.0 \(\pm\) 0.0 b & 4.0 \(\pm\) 0.0 b & 4.4 \(\pm\) 0.0 a & 4.5 \(\pm\) 0.0 a & 4.4 \(\pm\) 0.0 a & 4.5 \(\pm\) 0.0 a \\ \hline \hline \end{tabular}
\end{table}
Table 1: Physicochemical parameters of ggi-berry fermented wines.  
The total SO\({}_{2}\) content in these goji berry wines was much higher than that in goji berry fruits before the fermentation (Table 1). Potassium metabisulfite was added to terminate the fermentation process in this study, which resulted in the elevation of SO\({}_{2}\) content in these wines. Meanwhile, the yeasts used in this study also possessed the ability of produce SO\({}_{2}\) during the fermentation.