# Influence of Electrohydrodynamics on the Drying Characteristics and Volatile Components of Ginger
## 3 Results and Discussion
### Volatile Components  
Ginger includes several chemical ingredients, including phenolic components, volatile compounds (VOCs), and polysaccharides. Volatile organic compounds (VOCs) are among the most beneficial components in ginger because of their functional qualities, which include anti-inflammatory, antioxidant, and analgesic activities [42]. To investigate the volatile components in dried ginger under different drying conditions, gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to determine the volatile components and compounds in dried ginger under different drying voltage conditions. The volatile components and their relative concentrations in dried ginger were examined and identified. A total of 248 volatile organic compounds (VOCs) were found in dried ginger products, but the amounts of volatile compounds varied depending on the drying method used. Among these, 151 volatile compounds were found in the 30 kV group, 163 in the 25 kV, 160 in the 20 kV, 152 in the 15 kV, and 168 in the control group. These volatile chemicals belonged to seven classes: 44 alkanes, 34 esters, 27 aldehydes, 72 alcohols, 32 terpen, 22 ketones, and 17 others. Figure 6 shows the number of volatile component species in ginger after drying at various drying voltages. The concentration of volatile components can be utilized as a key indicator to distinguish ginger that was dried using different processes. As shown in Figure 7, the volatile components in ginger are primarily terpenoids and hydrocarbons. After electrohydrodynamic drying, the terpenoids in ginger were reduced, with 30 kV having the lowest terpenoids content (36.68%) and the control group having the highest (47.18%). The second-most abundant material was hydrocarbons, which remained rather stable following electrohydrodynamic drying, varying around roughly 20%. Ester compounds were the next largest level, increasing when compared to the control group, with the 15 kV experimental group having the highest ester content of 20.94%. Alcohol compounds also increased, reaching a maximum of 14.32% at 15 kV. After electrohydrodynamic drying, the content of ketones fell and that of aldehydes increased, while the concentration of other chemicals remained relatively constant. [PERSON] et al. [43] found that terpenes were the main volatile components of ginger, representing the main odor information of ginger; the volatile content of fresh ginger was higher than that of dried ginger, and the odor of hot air-dried ginger was the strongest compared with that of vacuum-dried, sun-dried, and vacuum-freeze-dried. The results of the rapid GC-electronicolfactory sensory evaluation showed that the hot air drying could retain more of the unique pungent and irritating odors of dried ginger. This was consistent with our results. Figure 8 depicts the fingerprint spectra of volatile compounds in ginger after electro-hydrodynamic drying at different voltages. Fingerprint spectra were drawn based on the peak retention time and peak area parameters of these compounds. In Figure 8, at 1.2-2.2, the peak value of the control group is higher. At 30.5-32.0, the experimental group has a high front. The rest of the positions have the same position of the common peaks of each sample, indicating that the samples have good consistency. The established fingerprints can be used to evaluate the quality of ginger. Figure 6: Types and amounts of volatile components of ginger at different drying voltages. Figure 7: Volatile constituent species content of ginger at different drying voltages. (**a**): 30 kV; (**b**): 25 kV; (**c**): 20 kV; (**d**): 15 kV; (**e**): The control group. This paper presents the structural identification of the volatile chemical constituents of ginger in combination with retention indices after a search of the mass spectrometry standard spectral library (NIST). The retention index indicates the behavior of the retention value of a substance in a stationary solution and has the advantages of good reproducibility, homogeneity, and small temperature coefficient.