## 4 Conclusions  
The volatile fingerprints of four native apricot cultivars planted in the Heshuo area of Xinjiang, China have been identified using HS-SPME-GC-MS/MS. Moreover, the multivariate analysis, i.e., partial least square discrimination analysis (PLS-DA) model, was successively performed to discriminate the differences in volatile compounds and provided a good cluster to classify the volatile substances of the different apricot cultivars. The biomarkers of volatiles in each apricot were found based on the variable importance for the projection analysis. As a result, a total of 63 volatile compounds, including 14 alcohols, 6 acids, 6 esters, 15 aldehydes, 13 ketones and 9 terpen, were acquired. Seven characteristic components could be taken as biomarkers of volatile compounds in four apricot cultivars, which were damascenone for Daibaiyou apricots; acetophenone, myrcenol and 7-hexadecenal for Luopuhongdaike apricots; 2,4-dimethyl-cyclohexanol for You apricots; eucalypt and salicaldehyde for Xiaobai apricots. Furthermore, the highest concentrations of sucrose and malic acid were present in Xiaobai apricots. Soluble solids content,  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Volatile Compounds**} & \multirow{2}{*}{**RI**} & \multicolumn{4}{c}{**Apricot Cultivars**} \\ \cline{3-6}  & & & **DBY** & **LPH** & **YOU** & **XB** \\ \hline
1 & Acetophenone & 1115 & \(-\) & \(+\) & \(-\) & \(-\) \\
2 & Eucalypt & 1237 & \(-\) & \(-\) & \(-\) & \(+\) \\
3 & Myrcenol & 1585 & \(-\) & \(+\) & \(-\) & \(-\) \\
4 & 2,4-Dimethyl-cyclohexanol & 1610 & \(-\) & \(-\) & \(+\) & \(-\) \\
5 & Salicylaldehyde & 1672 & \(-\) & \(-\) & \(-\) & \(+\) \\
6 & Damascenone & 1971 & \(+\) & \(-\) & \(-\) & \(-\) \\
7 & 7-Hexadecenal & 2144 & \(-\) & \(+\) & \(-\) & \(-\) \\ \hline \hline \end{tabular}
\begin{tabular}{l} DBY, Dabaiyou apricot; LPH, Luopuhongdaike apricot; YOU, You apricot; XB, Xiaobai apricot. The \({}^{\prime}\)+\({}^{\prime}\) means that the volatile compound was detected. \\ \end{tabular}
\end{table}
Table 4: The biomarkers for the four different apricot cultivars.  
Figure 5: The heatmap analysis of the volatile compounds (VIP \(>\) 1) in four different apricot cultivars. DBY, Dabaiyou apricot; LPH, Luopuhongdaike apricot; YOU, You apricot; XB, Xiaobai apricot.  
total phenolic content and total flavonoid content of Xiaobai apricots were higher than those determined in Dabaiyou, You and Luopuhongdaike apricot cultivars. This study not only provides a feasible approach to analyzing the characteristic volatile compounds from different apricot cultivars but also sets up a theoretical basis for developing apricot-flavored foods in practical production.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/foods11152297/sl](https://www.mdpi.com/article/10.3390/foods11152297/sl)]([https://www.mdpi.com/article/10.3390/foods11152297/sl](https://www.mdpi.com/article/10.3390/foods11152297/sl)). Figure S1: The chromatograms in the HS-SPME-GC-MS/MS analysis of the four different apricot cultivars. Figure S2: The loading graph of PLS-DA analysis of volatile compounds in four different apricot cultivars. Figure S3: The volatile compounds of VIP > 1 in four different apricot cultivars. Table S1: Concentration of volatile compounds in four apricot cultivars (\(\mu\)g/kg).  
Investigation, writing--original draft preparation, C.Z.; supervision, writing--review and editing, W.C.; review and editing, B.W.; methodology and formal analysis, J.S., X.P. and X.S. All authors have read and agreed to the published version of the manuscript.  
This study was supported by the National Natural Science Foundation of China (No. 31960465; No. 31560446; No. 31800828) and Xinjiang Production and Construction Corps (No. 2019 AB025; No. 2020 AB014).  
Not applicable.  
Data Availability Statement: Data is contained within the article or supplementary material.  
The authors declare they have no conflict of interests.