## 2 Results
### Effect of Low-Sodium Salts on the Aroma of Dry-Cured Meat  
#### 2.2.1 Volatile Compound Profile  
The types of volatile organic compounds in raw pork are relatively few, but multiple types of volatile compounds are formed after dry-curing, resulting in a richer flavor. However, the number of volatile compounds in dry-cured meat was still much less than that in dry-cured ham [27]. Compared with dry-cured ham, dry-cured meat had a shorter manufacturing time (around three months versus 12 months). According to Supplementary Table S1, a total of 55 different volatile compounds from nine different chemical groups were identified in the finished dry-cured meat by HS-GC-MS, including 12 aldehydes, 12 esters, 8 alcohols, 8 ketones, 5 alkanes, 2 pyrazines, 4 aromatics, 3 olefins, and 1 furan compounds. As shown in Figure 3, aldehydes were the most abundant volatile compounds. Aldehyde compounds in each group accounted for 42.49%-64.42% of the total volatiles, among which SP accounted for the highest proportion of 64.42%. The closest proportion to S (46.13%) was SM (42.49%). The order of aldehyde proportion content was SP \(>\) SPM \(>\) SPMA \(>\) S \(>\) SM, and there was no significant difference between each group. In addition, SM's proportions of total volatiles of esters, ketones, aromatics, and furans was also closest to that of S. The proportion of alcohols in each group was in the order of SPM \(>\) SM \(>\) SP \(>\) S \(>\) SPMA. The proportion of alcohols in SPM was significantly higher than that in S and SPMA. The proportion of esters in each group was SPMA \(>\) SM \(>\) S \(>\) SPM \(>\) SP, and the proportion of esters in SPMA was significantly higher than that in SP. The proportions of ketones and alkanes in each group were SPMA \(>\) SPM \(>\) SP \(>\) SM \(>\) S, and SPMA, SPM, and SP were significantly higher than S. The proportion of pyrazines in each group was SP \(>\) S \(>\) SPM \(>\) SM. SP was significantly higher than SM, and SPMA did not contain pyrazines. The proportion of aromatics in each group was S \(>\) SM \(>\) SP \(>\) SPM \(>\) SPMA, and S was significantly higher than SPMA. The proportion of furans in each group was SM \(>\) SPMA \(>\) SP \(>\) S \(>\) SPM, and there was no significant difference between the groups. In terms of compound types, S, SPMA, SPM, SP, and SM had 34, 39, 41, 38, and 41 volatile compounds, respectively. The findings showed that the addition of low-sodium salt increased the species of volatile compounds in dry-cured meat. Importantly, the SPMA, SPM, and SM groups containing Mg\({}^{2+}\) had more volatile compounds than SP, which contains KCl. Figure 3: Percentage of various volatile compounds in the total volatile compounds. Different letters in the same group indicate significant differences (\(p<\) 0.05; Tukey test) among treatments. S: 100% NaCl; SPMA: 59.375% NaCl+28% KCl+12% MgCl2+0.625% L-arginine (Arg); SPM: 60% NaCl+28% KCl+12% MgCl2; SP: 72% NaCl+28% KCl; SM: 88% NaCl+12% MgCl2. It was noteworthy that the total concentration of aldehydes was highest in dry-cured meat compared to other compounds, which was consistent with the results in dry-cured ham [28]. It can be seen from Supplementary Table S1 that the total content of aldehydes in all groups showed the following pattern: SP > SM > SPM > SPMA > S, among which the aldehydes content in SP was significantly higher than that of SPMA and S. Among the 12 aldehydes, the OAV values of 3-Methylbutanal, 2-Methylbutyal, Pentanal, Hexanal, Heptaldehyde, Octyl aldehyde, 1-Nonanal, (_E_)-2-Heptanal, (_E_)-2-Octenal, Decyl aldehyde, and (_E_)-2-Nonenal were greater than 1 (Table 2). It is generally accepted that compounds with OAV > 1 play an important role in overall odor [29]. 3-Methylbutanal and 2-Methylbutyal originate from the degradation of amino acids [29], and these compounds contribute positively to the sensory quality of dry-cured meat products, contributing to the overall aroma by providing cheesly, nutty, and salty notes [26].