# Analysis of the Aroma Chemical Composition of Commonly Planted Kiwifruit Cultivars in China
## 3 Results and Discussion
### Aroma Characteristics of Kikifruitus Characterized by E-Nose  
#### 3.2.1 E-Nose Response to Kiwifruit Samples  
The aroma of kiwifruit is one of the important characteristics for consumer acceptance and preference for high-quality kiwifruit, and it is also one of the intuitive feelings of consumers when judging the quality of kiwifruit. To more accurately simulate consumers' perception of the aroma of kiwifruit, based on HS-SPME-GC-MS analysis, E-nose was used to analyze the aroma characteristics of 23 kiwifruit cultivars. Figure S2 shows the E-nose responses of different kiwifruit samples. The x-axis is time, and the y-axis is the relative resistivity, that is, the ratio of sample gas to pure air resistivity (G/G0). Each curve  
Figure 2: Cluster heat map analysis (**A**) was performed on all volatile components in the kiwifruit samples, and a simplified cluster map (**B**) is presented (I–III: three major categories based on the GC-MS date).  
represents the change trend of the corresponding sensor, eventually reaching equilibrium over time, and all varieties of kiwifruit samples reach equilibrium within 50-70 s.  
For all kiwifruit samples, S7 (sensitive to many sulfur organic compounds and terpenes), S2 (sensitive to many sulfur organic compounds and terpenes), S6 (sensitive to many sulfur organic compounds and terpenes), and S8 (alcohol, sensitive to aromatic compounds with broad range, similar to No.6) response values increased significantly, while the response values of the remaining sensors hardly changed. After equilibrium, the response values of different varieties of kiwifruit showed significant differences. According to the response values of different sensors after balancing, all varieties of kiwifruit were roughly divided into four categories, which are shown as A-D in Figure S2. In category A kiwifruit, S7 had the highest response value, followed by S6, S2, and S8. In category B kiwifruit, the response value order was S7 \(>\) S2 \(>\) S6 \(>\) S8. In category C kiwifruit, the response value was, from high to low, S2, S7, and S6. In category D kiwifruit, the response values were S6, S7, S8, and S2 from high to low. Among the above four types of kiwifruits, S7 showed a higher response value, while in category C kiwifruits, S8 showed almost no change, and S2 and S7 were almost equal after reaching equilibrium. The response trend curve of the imported cultivar Sungold was category A, and its more prominent characteristic was that it reached equilibrium faster and the fragrance loss was slower. The introduced cultivar Hort16A also belonged to category A. However, overall, there was no significant difference between the two and other category A kiwifruits. The introduced variety Hayward belonged to category B, and there was no significant difference from other category B kiwifruits.  
[PERSON] et al. [9] obtained the same trend in aroma research of red-fleshed kiwifruit as we did in this experiment. Studies showed that the response values of S7, S2, S6, and S8 increased significantly, while the response values of the remaining sensors hardly changed. However, the response values were different, which may be caused by different instrument settings or samples.