# Highland Barley Replaces Sorghum as Raw Material to Make Shanxi Aged Vinegar
## 3 Results and Discussion
### Constituent Analyses during Vinegar Production
#### 3.2.3 Analyses of the Main Components in New and Aged Vinegars  
Aging in an open pottery container is a unique process of SAV production [19]. In the ageing process of SAV, with the evaporation of volatile substances and water, the volume and viscosity (thickness) of the vinegar decreases and increases, respectively, and the pungent taste reduces, which makes the vinegar more mellow, soft, and harmonious. Meanwhile, due to the esterification and Maillard reactions, various components in vinegar also change considerably [37]. The main composition of the new (fresh) and aged (one and a half years) HBV and SV were determined and compared (Table 3). The results (Table 3) revealed that, compared with the new vinegars, with the exception of RS and TE, the main components of the aged vinegars were improved to a certain extent. At the end of ageing, due to the evaporation of volatile components and water in vinegars, the volumes of aged HBV and SV were only about two-thirds of those of the new vinegars, and the viscosity and consistency of the aged vinegars were also improved to a great extent. The RS reduction in aged vinegars may be caused by the RS consumption of the Maillard reaction during the ageing process, while the TE decreases may be due to its  
Figure 3: Changes of alcohol and TA concentrations during AAF. \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Items**} & \multicolumn{2}{c}{**New Vinegars**} & \multicolumn{2}{c}{**Aged Vinegars**} \\ \cline{2-5}  & **HBV** & **SV** & **HBV** & **SV** \\ \hline TA (g:100 mL\({}^{-1}\)) & 4.94 \(\pm\) 0.04 & 4.93 \(\pm\) 0.02 & 6.65 \(\pm\) 0.06 & 6.55 \(\pm\) 0.05 \\ Non-volatile acid (g:100 mL\({}^{-1}\)) & 1.62 \(\pm\) 0.01 & 1.66 \(\pm\) 0.02 & 2.75 \(\pm\) 0.04 & 1.94 \(\pm\) 0.02 \\ Amino acid nitrogen (g:100 mL\({}^{-1}\)) & 0.20 \(\pm\) 0.01 & 0.21 \(\pm\) 0.02 & 0.31 \(\pm\) 0.04 & 0.31 \(\pm\) 0.02 \\ RS (g:100 mL\({}^{-1}\)) & **1.24 \(\pm\) 0.01** & **1.24 \(\pm\) 0.01** & **0.99 \(\pm\) 0.02** & **0.88 \(\pm\) 0.04** \\ Salt (g:100 mL\({}^{-1}\)) & 0.89 \(\pm\) 0.02 & 0.82 \(\pm\) 0.03 & 1.03 \(\pm\) 0.03 & 1.53 \(\pm\) 0.03 \\ Soluble salt-free solid (g:100 mL\({}^{-1}\)) & 9.46 \(\pm\) 0.05 & 8.16 \(\pm\) 0.02 & 14.10 \(\pm\) 0.11 & 13.64 \(\pm\) 0.04 \\ TE (g:100 mL\({}^{-1}\)) & **3.13 \(\pm\) 0.06** & **3.50 \(\pm\) 0.03** & **2.70 \(\pm\) 0.02** & **3.35 \(\pm\) 0.05** \\ TF (mg:100 mL\({}^{-1}\)) & 73.91 \(\pm\) 0.19 & 88.71 \(\pm\) 0.03 & 109.00 \(\pm\) 1.41 & 113.00 \(\pm\) 1.39 \\ Liquidrazine (mg:100 mL\({}^{-1}\)) & 3.05 \(\pm\) 0.05 & 3.35 \(\pm\) 0.04 & 5.49 \(\pm\) 0.08 & 9.13 \(\pm\) 0.02 \\ \(\beta\)-glucan & - & - & - & - \\ Volume (L) & **100.00 \(\pm\) 0.71** & **100.00 \(\pm\) 0.98** & **68.00 \(\pm\) 0.69** & **69.00 \(\pm\) 0.92** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The main composition in HBV and SV before and after aging. high volatility [38]. Both the TA and non-volatile acid in the aged vinegars were greatly improved. The TA increase may be mainly caused by the increase of the contents of the non-volatile acids [39]. A higher concentration of non-volatile acids, such as lactic acid, succininic acid, and gluconic acid, together with a higher content of soluble salt-free solid can neutralize and reduce the pungent smell of volatile acids, such as acetic acid, so as to make the vinegars more soft and harmonious [40,41]. The characteristic component of SAV, ligustrazine (2,3,5,6-tetramethylpyrazine), also one of the products of the Maillard reaction [42], and TF, both of which have many physiological functions, such as dilating blood vessels, lowering blood pressure, and improving cerebral blood circulation, anti-cancer, anti-bacteria, anti-virus, and antioxidant functions, etc. [43,44,45,46], were also greatly improved after aging. Ligustrazine and TF are considered to be the material basis of various physiological functions of SAV [47,48].