## 3 Results  
### GC-IMS Analysis  
#### 3.1.1 GC-IMS Topographic Plots and Fingerprints  
GC-IMS utilizes ion mobility in the buffer to effectively separate and identify aroma compounds. Moreover, it enables rapid and accurate acquisition and visualization of IMS data for VOCs present in yellow horn seed oil. Figure 2A shows the 3D topographic of the VOCs in yellow horn seed oil roasted at different temperatures, with the red color indicating a higher content. Although the VOCs in yellow horn seed oil roasted at different temperatures exhibit similarities, there are slight variations in their signal intensity. As depicted in Figure 2A(a), an increase in roasting temperature leads to a rise in the majority of aroma substances. Additionally, certain constituents exhibit an inverse relationship with temperature, as depicted in Figure 2A(b). This finding is consistent with [PERSON] et al.'s [PERSON] et al. (2016) study on a microwave treatment applied to rapeseed oil. The kinds and concentrations of VOCs were compared precisely in the range of 120-170 \({}^{\circ}\)C in a 2D topographic (Figure 2B). The reference spectrum at 120 \({}^{\circ}\)C was utilized, and the spectra of other temperatures were obtained via subtraction. The red area in the figure indicates a higher VOC content than the reference, while the blue indicates a lower concentration. As depicted in Figure 2B, the proportion of red compound area gradually increases with roasting temperature.  
The VOC fingerprint of yellow horn seed oil was constructed to accurately represent the variations in VOC content resulting from different roasting temperatures (Figure 2C). Each row represents the signal peaks for different samples, while each column represents a distinct volatile compound. The brightness of the color is proportional to the VOC content, with higher concentrations resulting in a more intense red hue and lower concentrations, producing a brighter blue shade. Five areas (a, b, c, d, e) marked with wireframe exhibit elevated content of VOCs in the different samples of the yellow horn seed oil treated at 120-170 \({}^{\circ}\)C. The concentration of volatile components in a-region reached the highest in the sample of 160 \({}^{\circ}\)C, with nine VOCs present, including 2-pentenal (isomer), ethyl valerate and 2-methylpyrazine. The b-region exhibited the highest concentration of VOCs in the 120 \({}^{\circ}\)C sample, including 3-hydroxy-2-butanone ethyl acetate, 1-octen-3-ol and additional ten VOCs. Meanwhile, the c-zone was dominated by ten VOCs, such as 2,3-butanedione, 2,3-pentanedione and heptanal in the 130 \({}^{\circ}\)C sample. The d-region contained six VOCs, with the highest concentration observed in the 140 \({}^{\circ}\)C sample. These compounds included  
Figure 2: GC-IMS topographic plots and fingerprints of the yellow horn seed oil. **(A)** 3D topographic. **(B)** 2D topographic subtraction plots of the VOCs. **(C)** VOC fingerprint comparisons of the yellow horn seed oil.  
furfurfuryl mercaptan, 3-hexenyl acetate (isomer), 3-hexen-1-ol (isomer), etc. In contrast, the e-zone was dominated by 2-heptenal (isomer), 2-pentylfuran, and 2-octenal (isomer), among other VOCs. The 170 \({}^{\circ}\)C sample had the highest concentration of these aroma substances. The results above suggest that the volatile components in yellow horn seed oil samples roasted at different temperatures vary significantly (\(p<0.05\)), indicating a significant impact of roasting temperature on the aroma profile of the oil.