# Effects of Process Parameters on the Quality of Suantang Beef
## 3 Results and Discussion
### Quality Analysis of ST Beef and Boiled Beef
#### 3.6.3 Volatile Compounds in ST Beef and Boiled Beef  
A total of 169 volatile compounds were quantified, including 50 hydrocarbons, 29 esters, 30 alcohols, 8 sulfides, 4 phenols, 11 ketones, 18 aldehydes, 5 acids, and 14 other compounds (Table S1). Hydrocarbons, esters, and alcohols are the main volatile compounds in our samples. To further examine the contribution of these 169 volatile carbides to the overall aroma characteristics of ST beef, their OAV were calculated, taking into account their concentration and odor thresholds (Table S1). Figure 5 illustrated the changes in volatile compounds in ST, ST Beef, and boiled beef. The hydrocarbon concentration in beef increased from 689.949 \(\upmu\)g/100 g to 917.386 \(\upmu\)g/100 g after ST cooking, combined with Table S1, hydrocarbons such as copaene, \(\upbeta\)-sesquiphellandrene, \(\upbeta\)-bisabolene, \(\upbeta\)-elemene, zingiberene increased significantly. [PERSON], et al. [1] found that HST has high levels of terpen, including \(\upbeta\)-sesquiphellandrene, \(\upbeta\)-myrcene, \(\upbeta\)-elemene, \(\upbeta\)-bisabolene, \(\upalpha\)-pinene, \(\upalpha\)-farmesene, D-limonene, copaene, and \(\upalpha\)-curcumene, were mainly derived from raw materials and excipients, such as tomatoes, red peppers. At the same time, the concentration of esters in beef increased from 689.940 \(\upmu\)g/100 g to 917.386 \(\upmu\)g/100 g after cooking in ST.  
Esters are derived from the esterification of carboxylic acids and alcohols. Esters with short-chain acids have a fruity and sweet taste, but long-chain acids produce a fatty odor [47]. Notably, beef produces two characteristic esters after cooking in ST, linalyl acetate and 4-terpinenyl ester of isobutanoic acid. Among them, linalyl acetate has a higher OAV value, which can be considered the main contributor to the aroma of ST beef. At the same time, the content of some esters decreased significantly, such as isoamyl acetylacetate, \(\upalpha\)-terpinyl acetate, and linalyl propionate. It was maybe that ST inhibited the volatilization of these esters in beef. Alcohols are mainly produced by the oxidative decomposition of lipids [48] because of their high odor threshold and are considered to contribute little to the aroma of meat samples [49]. The carbon chain length can produce a unique aroma [50]. This study showed that the alcohol content in beef increased from 489.134 \(\upmu\)g/100 g to 565.497 \(\upmu\)g/100 g. The contents of geraniol, 2-heptanol, linalool, (-)-terpene-4-ol, and 1-hexanol in ST beef increased compared with the control group. Among them, geraniol and linalool are high, with sweet and pleasant flower fragrance [51], and linalool found in ham, salchichon, shoulder, and cecina contributes to flowery and citrus aroma [52]. Their content and OAV value increased significantly, which could be considered the primary source of ST beef and ST.  
Figure 5: Changes in volatile compounds content in ST, ST beef, boiled beef. Aldehydes could impart a pleasant fruity and fatty sensorial note to meat products [53]. It is the main component of beef volatile flavor [54]. The aldehyde concentration in beef reduced from 758.444 \(\upmu\)g/100 g to 402.461 \(\upmu\)g/100 g after cooking in ST, while the aldehyde content in the ST was as low as 0.808 \(\upmu\)g/100 g. Aldehydes are derived from the oxidation, degradation, or strecker degradation reactions of amino acids in meat fat [55], which explains the low aldehyde content in the ST. Aldehydes are readily reduced to alcohols or oxidized to acids in the presence of microorganisms [56], which may account for the lower aldehyde content and the increased alcohol content. Nonanal, octanal, benzaldehyde, and lemongrass aldehyde were detected in both beef and ST beef showing high concentrations and OAV. These substances provided sweetness to the beef and rose, citrus, and oil aromas that added to the smell of the meat [57].