## 3 Results
### Amino Acid Content of a Fermented Mushroom Beverage (FMB)  
FMB samples measured the presence of amino acids at 0 and 720 h, as shown in Table 1. All of the amino acids werefound in FBM, except cysteine, lysine, and methionine. There were four amino acids: alanine, isoleucine, leucine, and valine, which appeared in high amounts. The initial total amino acid content of FMB with and without \(L\). _plantarum_ SK15 was not significantly different. The total amino acid content increased from 991.35 to 1059.27 ug/L in FMB without \(L\). _plantarum_ SK15. In comparison, the total amino acid content decreased from 998.05 to 845.80 ug/L in the sample inoculated starter \(L\). _plantarum_ SK15.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Amino Acid Content 1 (ug/L)**} \\ \cline{2-5}
**Amino Acid** & \multicolumn{2}{c}{**0 h**} & \multicolumn{2}{c}{**720 h**} \\ \cline{2-5}  & **Without Starter** & **With Starter** & **Without Starter** & **With Starter** \\ \hline Alanine & 138.65 \(\pm\) 2.03 c & 133.21 \(\pm\) 1.84 b & 145.03 \(\pm\) 2.21 d & 69.60 \(\pm\) 1.06 a \\ Arginine & 22.95 \(\pm\) 1.72 a & 23.30 \(\pm\) 1.50 a & 28.97 \(\pm\) 1.97 b & 23.40 \(\pm\) 1.45 a \\ Aspartic acid & 10.78 \(\pm\) 2.85 b & 9.91 \(\pm\) 0.87 ab & 11.86 \(\pm\) 1.99 b & 6.05 \(\pm\) 0.26 a \\ Cysteine & ND & ND & ND & ND \\ Glutamic acid & 65.09 \(\pm\) 2.97 b & 56.85 \(\pm\) 2.52 a & 69.28 \(\pm\) 0.85 b & 54.78 \(\pm\) 1.23 a \\ Glycine & 14.13 \(\pm\) 0.84 a & 17.58 \(\pm\) 1.37 ab & 19.40 \(\pm\) 2.38 b & 20.54 \(\pm\) 0.96 b \\ Histidine & 2.25 \(\pm\) 0.20 b & 2.68 \(\pm\) 0.14 b & 3.22 \(\pm\) 0.24 c & 1.39 \(\pm\) 0.10 a \\ Isoleucine & 173.99 \(\pm\) 2.08 b & 176.22 \(\pm\) 2.28 b & 178.86 \(\pm\) 2.95 b & 165.44 \(\pm\) 1.55 a \\ Leucine & 184.96 \(\pm\) 2.87 b & 192.88 \(\pm\) 2.08 c & 190.69 \(\pm\) 1.76 c & 177.79 \(\pm\) 1.64 a \\ Lysine & ND & ND & ND & ND \\ Methionine & ND & ND & ND & ND \\ Phenylalanine & 101.81 \(\pm\) 2.73 b & 102.17 \(\pm\) 1.59 b & 108.62 \(\pm\) 1.17 c & 56.51 \(\pm\) 1.55 a \\ Proline & 38.01 \(\pm\) 0.89 a & 39.53 \(\pm\) 0.59 ab & 42.07 \(\pm\) 1.72 b & 47.50 \(\pm\) 1.42 c \\ Serine & 7.24 \(\pm\) 0.24 c & 5.72 \(\pm\) 0.44 b & 5.29 \(\pm\) 0.36 b & 2.30 \(\pm\) 0.28 a \\ Tyrosine & 50.81 \(\pm\) 1.11 c & 46.26 \(\pm\) 0.47 b & 57.62 \(\pm\) 1.07 d & 16.70 \(\pm\) 0.55 a \\ Threonine & 18.62 \(\pm\) 0.47 ab & 19.73 \(\pm\) 2.00 b & 24.54 \(\pm\) 1.15 c & 16.17 \(\pm\) 0.98 a \\ Valine & 162.06 \(\pm\) 1.51 a & 172.04 \(\pm\) 3.48 b & 173.83 \(\pm\) 0.93 b & 187.65 \(\pm\) 0.91 c \\ Total & 991.35 \(\pm\) 22.49 b & 998.05 \(\pm\) 21.16 b & 1059.27 \(\pm\) 20.75 c & 845.80 \(\pm\) 13.93 a \\ \hline \hline \end{tabular}  
* Mean value \(\pm\) standard deviation with different letters (a, b, c, and d) in the same row indicate significant differences during fermentation time among FMB (\(p<\) 0.05). ND was not detected.  
\end{table}
Table 1: Total amino acid and free amino acid content of a fermented mushroom beverage (FMB) with and without starter culture \(L\). _plantarum_ SK15 during fermentation time at 0 h and 720 h.  
Figure 4: The change of ethanol content in a fermented mushroom beverage (FMB) with and without starter culture \(L\). _plantarum_ SK15 during fermentation time.