# Analysis of the Aroma Chemical Composition of Commonly Planted Kiwifruit Cultivars in China
## 4 Conclusions  
In summary, the aroma chemical compositions of 23 kiwifruit samples were analyzed through GC-MS and E-nose. The results indicated that 2-octanone and 3-octanone could be used as dual internal standard substances in HS-SPME-GC-MS detection and have the highest general applicability, with the smallest error (0.22-4.89% RSD). A total of 172 effective aroma components were detected, which were divided into 9 categories according to functional groups, including 37 esters, 17 alcohols, 13 aldehydes, 16 ketones, 4 acids, 20 alkanes, 40 alkenes, 16 aromatic hydrocarbons and their homologues, and  
Figure 5: Venn diagrams for analysis of volatile components in kiwifruit samples with different flesh colors (**A**) and varieties (**D**). The results of PCA of kiwifruit with different flesh colors based on GC-MS data (**B**) and E-nose response data (**C**). The results of PCA of kiwifruit of different varieties based on GC-MS data (**E**) and E-nose response data (**F**).  
9 other components. Among them, there were 16 main volatiles, 21 secondary volatiles, and 74 unique volatiles in kiwifruit. Esters, alcohols, and aldehydes had a greater effect on the aroma characteristics of kiwifruit. Ethyl butanoate, (E)-2-hexen-1-ol, and (E)-2-hexenal are core aroma components in kiwifruit, but still need further confirmation using Sensomics in the future. Moreover, the E-nose can effectively distinguish different cultivars of kiwifruit. Clustering based on the results of GC-MS and E-nose indicated a certain degree of similarity. However, kiwifruit cultivars with different flesh colors cannot be effectively distinguished by their aroma chemical compositions, while different species of kiwifruit (_A. chintensis_ and _A. deliciosa_) can be distinguished to some extent, but the effect was not satisfactory. The results show that the aroma chemical compositions of new Chinese breeds are more complicated, while for Sungold, the aroma dissipation rate is slower, and the aroma retention time is longer. These results provide a certain theoretical basis for the future breeding, planting, and marketing of kiwifruit.  
The following are available online at [[https://www.mdpi.com/article/10.3390/foods10071645/s1](https://www.mdpi.com/article/10.3390/foods10071645/s1)]([https://www.mdpi.com/article/10.3390/foods10071645/s1](https://www.mdpi.com/article/10.3390/foods10071645/s1)), Figure S1: Quantitative analysis of esters (A), alcohols and aldehydes (B), ketones, acids and alkanes (C), alkenes (D) and aromatic hydrocarbons and their homologs and other volatile components (E) in kiwifruit samples. The concentration of volatile components gradually increased from blue to red in units of \(\upmu\)g/L, Figure S2. Kiwifruit samples were divided into 4 categories based on electronic nose response (A)-(D). Electronic nose sensor (E). Table S1: Cultivars, species, flesh color, region and retail price of kiwifruits, Table S2. The determination of internal standards, Table S3. The concentration of volatile components in different cultivars of kiwifruit, Table S4. Total variance explained.  
Conceptualization and methodology, T.M., X.S. and Y.L.; formal analysis, T.L., C.G., Q.Y. and J.W.; data curation, T.M. and T.L.; writing--original draft preparation, T.M. and T.L.; writing--review and editing, T.M., H.Z. and T.L.; visualization, T.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the class General Financial Grant from the China Postdoctoral Science Foundation (2020M673505, 2020M673507), and the Science and Technology Innovation and Achievement Transformation project of Experimental Demonstration Station (Base) of Northwest A&F University (TCZX2019-33, TCZX2020-36), and the Shaanxi Key Research and Development Program (2020 NY-134, 2020 TD-047).  
The authors declare no conflict of interest.