## 2 Materials and Methods
### HS-SPME-GC-MS-O Analysis  
Volatile compounds were extracted using headspace solid-phase microextraction (HS-SPME) with a multifunctional autosampler (AOC-6000 plus, Shimadzu, Kyoto, Japan). Three independent extractions were carried out for each ham sample. Identification of the volatile compounds was performed using gas chromatography-mass spectrometry (GC-MS-TQ8040 NX, Shimadzu, Kyoto, Japan). As shown in Figure 2, prior to extraction, a smart SPME fiber (DVB/Carbon WR/PDMS, 80 \(\upmu\)m, Shimadzu, Muttenz, Switzerland) was conditioned for 30 min at 250 \({}^{\circ}\)C in the gas chromatograph injection port (Inlet). One gram of minced ham sample, with 5 \(\upmu\)L of an aqueous solution containing 53.4 mg/L of cyclohexanone (GC quality, Aladdin, Shanghai, China) as an internal standard, was placed in a 20 mL headspace vial and sealed with a screw cap. The compounds were extracted at 60 \({}^{\circ}\)C for 60 min in a heated stirrer after equilibrating at 60 \({}^{\circ}\)C for 2 min. The adsorbed compounds were then desorbed in the GC injector for 30 min at 250 \({}^{\circ}\)C. Volatile compounds were separated using an SH-Rxi-5 Sil MS capillary column (0.25 mm \(\times\) 0.25 \(\upmu\)m \(\times\) 30 m, Shimadzu, USA). Helium was used as the carrier gas with a column flow rate of 2 mL/min. The chromatograph oven temperature was as follows: 40 \({}^{\circ}\)C for 1 min, increased from 40 \({}^{\circ}\)C to 100 \({}^{\circ}\)C at 3 \({}^{\circ}\)C/min, held at 100 \({}^{\circ}\)C for 10 min, increased from 100 \({}^{\circ}\)C to 150 \({}^{\circ}\)C at 5 \({}^{\circ}\)C/min, held at 150 \({}^{\circ}\)C for 2 min, and finally increased from 150 \({}^{\circ}\)C to 250 \({}^{\circ}\)C at 10 \({}^{\circ}\)C /min with a 5 min hold. The MS operated in Q3 Scan mode over a range of \(m/z\) 33-500. Compounds were identified by comparing their mass spectra with the NIST20s mass spectral library. The concentration of each compound was calculated based on its area relative to the internal standard.  
graph by auxiliary gas (Helium) to a sniffing port and evaluated using a human's sense of smell (nose). To prevent nasal mucosa drying and to mitigate its negative effect on sensory perception during prolonged GC-MS-O analysis, the moist air generated in a bubbling bottle was introduced at the nose cone flange. The GC-MS conditions were consistent with those previously described. An olfactory voicegram device, consisting of an olfactory voicegram interface (VI277, GL Sciences, Tokyo, Japan) and a set of USB headphones, was used to record the names and details of odors alongside the chromatogram.  
A ten-member panel of assessors, comprising both sexes and aged between 20 and 30 years, was recruited for the GC-O analyses. The panelists were trained prior to the sensory evaluation to become familiar with odor descriptions. During the analysis, each panelist individually sniffed the GC effluent and reported their observations. The aromacative compounds detected were recorded along with their perceived intensity, quality, and hedonic assessment. Intensity, representing the strength of the aroma sensation, was classified into three levels: strong, middle, and weak. Aroma quality was described using standard descriptors, which are common terms that relate the aroma to known substances [19]. The aroma quality standards used in the experiments are shown in Table 2, including 10 aroma groups with examples of descriptor types. The hedonic assessment dimension was associated with the relative pleasantness or unpleasantness of the aroma and quantified on a scale from 1 (completely dislike) to 10 (very good, pleasant, and agreeable). Volatile compounds detected by more than two panelists were considered to have potential aroma activity [10].