## 3 Results and Discussion
### Detection of Aroma Substances in Beer
#### 3.4.2 GC-MS  
There were a total of 77 compounds in the GC-MS assay, and the beer compounds detected by GC-MS were divided into three categories: compounds with no significant difference, compounds with more LS than OWBL, and compounds with less LS than OWBL, which were added to the commercially available beer assay to test for volatiles of roughly the same composition as the commercially available beer. The reason for adding the commercially available beer was to test the volatiles to ensure that the brewing process was approximately the same as the commercially available pale lager. In this experiment, substances specific to a single commercially available lager were ignored, thus minimizing the effects of the use of different hop types and different fermentation processes, as well as different flavor substances produced by different brewing yeasts. The results are shown in Table 9.  
Figure 2: Electronic nose radar map of home-brewed lager in the laboratory and lager on the market.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**NO**} & \multirow{2}{*}{**Vulatile Compounds**} & **R1** & **CAS** & \multicolumn{4}{c}{**Relative Content (S)**} & \multicolumn{4}{c}{**Average Characteristic**} \\ \cline{2-10}  & & & & **OURL** & **LS** & **CAL\({}_{\rm{AL}}\)** & **  
It is the aroma profile of the LS that is illustrated in Table 9. The combination of GC-MS and an electronic nose can only characterize the composition of the flavor substances in beer and determine its flavor components. The characteristic aroma varies from lager to lager, and this aroma comes partly from the aroma of the raw materials and adjuncts themselves and partly from the yeast or metabolites produced during their fermentation. There are a total of 77 compounds in Table 9, and 51 substances were detected in sugarcane lager. Fifty-two compounds were found to be the same in the two commercially available lagers compared, of which esters and alcohols accounted for 80%, indicating that in sugarcane lager, alcohols and esters constitute the basic flavor; thirty-two compounds were common to the four lagers, and eleven substances were unique to sugarcane lager compared with the other three lagers, namely camphor, carbonochl, ethyl(E) cinnamate, acetophenone, 4-ethylbenzaldehyde, cyclododecane, ethyl myristate, m-phthalaldehyde, phenethyl camphor, carbonochl, and ethyl(E) cinnamate, which were found to be contained in the sugarcane syrup itself after comparison with the sugarcane syrup and word components. These are the flavor substances of the sugarcane syrup itself and the flavor substances obtained by yeast fermentation of the sugarcane syrup. At the same time, compared with commercially available whole-barley lagers, laboratory whole-barley lagers produce unique substances, such as 2-acetylpyrrole, gamma-nonanolactone, etc. These substances can be considered to be produced by the overfermentation of word by yeast under laboratory conditions, but they are not present in laboratory sugarcane lagers, and the possible reason for this analysis is because brewer's yeast can produce substances such as acetophenone by the joint action of word and sugarcane syrup, but it is not possible to conclude that acetophenone, 4-ethylbenzaldehyde, cyclododecane, ethyl myristate, m-phthalaldehyde, phenethyl hexanoate, methananone, (4-ethylphenyl)phenyl-, and ethyl palmitate are produced by the yeast metabolism of sugarcane syrup or by yeast synergism of sugarcane syrup and word. It is presumed that it is mainly produced by the yeast using amino acids (such as histidine) that are not readily available in the post-fermentation stage, combined with the sugar in the sugar cane syrup.