## 2 Results
### HS-SPME-GC-MS Studies of Volatiles in Soybean Oil at the End of Accelerated Oxidation  
To further understand the effect of QG on the oxidative stability of soybean oil subjected to accelerated oxidation, HS-SPME-GC-MS was used to analyse the volatile compounds (Table S2). Analyses of the volatile components in soybean oil identified 108 volatile components, including 16 alcohols, 23 aldehydes, 25 ketones, 4 acids, 15 esters, 18 hydrocarbons and 7 others (Figure 5a). Compared with the control group, the amounts and contents of volatile components were significantly reduced by antioxidant treatment. The most dramatic declines were seen for soybean oil treated with PG and QG. Specifically, the CK group contained 69 volatile constituents representing 63.9% of the total, while the QG and PG groups only exhibited 17.6% and 14.8% total volatile components (Figure 5b). Using a Venn diagram, we observed that these volatile components comprised seven components, including hexanal, octanal, trans-2-heptenal, (E)-2-octenal, butanoic acid, 2,2-dimethyletenyl ester, trans, trans-2,4-nondienal and trans, trans-2,4-decadien-1-al, which were observed for all groups (Figure 5c). Additionally, the highest proportion of volatile components (46.36% of the total peak area) was found for the CK group, while the QG and PG groups only accounted for 1.45% and 0.87% of the total peak areas (Figure 6). In conclusion, the addition of QG retarded the production of volatile components in soybean oil and blocked the production of acids and alkanes. Moreover, the antioxidant capacity of QG was comparable to that of the known antioxidant (PG) but significantly better than those of BHT and TP. Most importantly, the trend for the degree of inhibition of volatile profiles was consistent with the trends for the peroxide value, acid value and fatty acid content.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**No.** & **Chemical Name** & \multicolumn{5}{c}{**Mean Peak Area of Fatty Acids (\(\times 10^{6}\))**} \\ \cline{3-6}  & & **CK** & **QG** & **PG** & **BHT** & **TP** \\ \hline
6 & 11,14-Octadecidenoicacid, methyl ester & C18:2 & ND & ND & ND & \(0.12\pm 0.015\) & ND \\
7 & (9E,11E)-9,11-Octadecidenoic & & & & & \\  & & & & & & \\  & methyl ester & & & & & \\  & Methyl ester of cla & & & & & \\
8 & (9-cis, 11-trans) & C18:2 & 0.06 \(\pm\) 0.03 b & ND & \(0.27\pm 0.07\) a & ND & ND \\
9 & (9-cis, 11-trans) & C22:0 & 0.05 \(\pm\) 0.01 a & 0.063 \(\pm\) 0.006 a & 0.05 \(\pm\) 0.01 a & 0.0367 \(\pm\) 0.06 b & 0.057 \(\pm\) 0.01 a \\
10 & Methyl palmitate & C16:0 & 1.17 \(\pm\) 0.19 b & 1.3 \(\pm\) 0.04 ab & 1.41 \(\pm\) 0.1 ab & 1.42 \(\pm\) 0.23 ab & 1.48 \(\pm\) 0.13 a \\
11 & Methyl stearate & C18:0 & 0.51 \(\pm\) 0.07 b & 0.58 \(\pm\) 0.03 ab & 0.6 \(\pm\) 0.03 ab & 0.61 \(\pm\) 0.11 ab & 0.65 \(\pm\) 0.06 a \\
12 & Caprylic acid methyl ester & C8:0 & ND & ND & ND & ND & \(0.06\pm 0.005\) \\
13 & Methyl arachid & C20:0 & ND & 0.047 \(\pm\) 0.005 a & ND & \(0.04\pm 0.017\) a & 0.047 \(\pm\) 0.01 a \\
14 & Dimethyl2 acetate & C10:0 & 0.07 \(\pm\) 0.01 a & ND & ND & ND & \(0.09\pm 0.005\) b \\ \hline \hline \end{tabular} Note: “ND” indicates not detectable. Values are means \(\pm\) SD (one-way ANOVA, \(n=3\), SPSS Statistics). Significant differences between diet groups at the indicated week are signified by letters, where different letters indicate difference (\(p<0.05\)) between groups, while the same letter indicates no difference.  
\end{table}
Table 3: _Cont._