## 3 Results  
The extract yield of phenolic acids and flavonoids from the WCR samples was observed for WCR LAB-inoculated silage Stages 1, 2, and 3 (1301.51, 1445.73, and 1456.25 mg/5 g), followed by WCR silage LAB-noninoculated silage Stage 1, 2, and 3 (1271.23, 1387.47, and 1376.58 mg/5 g), WCR hay (1415.16, 1487.15, and 1490.32 mg/5 g), and WCR fresh freeze-dry sample (987.33, 1012.47, and 1065.15 mg/5 g). The quantified phenolic acids and flavonoids in the WCR silage materials are shown in Table 3. The phenolic acid and flavonoid contents in the LAB-inoculated and noninoculated WCR silage samples showed no remarkable differences between these two samples. However, myricetin was quantified at 1.14 \(\upmu\)g/g in the milk stage and not identified in the heading and booting stages of the LAB-inoculated WCR silage sample. In addition, the concentrations of flavonoids and phenolic acids were slightly higher at the milk stage except for those of rutin and chlorogenic acid compounds, compared to other stages (Table 3). Luteolin was detected at the milk stage but not detected at the booting stage of the WCR sample. However, the quercetin, rutin, prophyl gallate, and caffe acid contents were observed to have no significant changes at the milk stage of both the LAB-inoculated and noninoculated WCR extracts. Therefore, LAB inoculation did not alter the phenolic acid and flavonoid contents of fermented WCR silage. Chlorogenic acid, rutin, and luteolin at the milk stage were increased slightly in LAB-noninoculated WCR silage than in the LAB-inoculated WCR silage; they were 0.77, 1.15, and 0.58 \(\upmu\)g/g, respectively, and they were higher at the milk and heading stages than at the booting stage of WCR silage samples (\(p<0.05\)). The flavonoid compounds, particularly luteolin and myricetin, were identified at the milk stage of LAB-noninoculated WCR silage, which was \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Time Step (min)**} & \multirow{2}{*}{**Elution Method**} & \multicolumn{2}{c}{**Solvent System**} \\ \cline{3-4}  & & **Solvent A (\%) 1\% Formic Acid in Water** & **Solvent B (\%) 95\% Acetonitrile** \\ \hline
0–25 & Gradient & 75 & 25 \\
25–35 & Gradient & 15 & 85 \\
35–45 & Gradient & 15 & 85 \\
45–48 & Gradient & 10 & 90 \\
48–65 & Gradient & 60 & 40 \\
65–75 & Gradient & 85 & 15 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Gradient elution for the HPLC–DAD mobile phase solvent system. not detected at the booting and heading stages of the LAB-inoculated WCR sample. It may be due to microbial community utilization as a nutrient or degradation into monomers in LAB-inoculated WCR silage (Table 3). The phenolic acid and flavonoid levels of WCR hay were also investigated. There were slight differences in phenolic acid and flavonoid contents between the three stages of harvest periods; in particular, the maximum phenolic acids and flavonoids were observed at the milky stage compared to the booting and heading stages of WCR hay. The WCR milk stage was quantified with higher concentrations of chlorogenic acid, prophyl gallate, luteolin, kaemferol, and quercetin (1.71, 0.79, 0.54, 1.29, and 1.28 ug/g, respectively; Table 3). However, chlorogenic acid, prophyl gallate, luteolin, kaemferol, and quercetin were lower at the booting stage, followed by the heading stage of WCR hay. The heading stage of WCR hay phenolic acids showed a similar trend to the milk stage: in particular, caffeic acid, ferulic acid, p-coumaric acid, chlorogenic acid, and prophyl gallate were 1.85, 1.81, 1.23, 1.74, and 0.82 ug/g, respectively, and the phenolic acid content was not significantly changed compared to the milky and heading stages. Furthermore, the quercetin and kaempferol contents gradually increased in all stages after heading, but most of the metabolites were increased in (milk) Stage 3 alone. Fresh freeze-dried WCR extract was analyzed for phenolic acid and flavonoid concentration at different harvesting periods, such as the booting, heading and milky stages.