## 3 Results and Discussion
### Volatile Flavor Profile during BBP-Meju Fermentation with Different Salt Concentrations
& 1142 & 74 & 2.54 \(\pm\) 0.46 & 1.91 \(\pm\) 0.24 & 2.31 \(\pm\) 0.72 & 3.97 \(\pm\) 1.06 & 8.01 \(\pm\) 0.43 & 6.16 \(\pm\) 0.81 \\ Pateland & 72.4-14.0 & 1250 & 88 & 16.09 \(\pm\) 3.36 & 15.23 \(\pm\) 3.36 & 17.28 \(\pm\) 3.39 & 420.2 \(\pm\) 5.10 & 28.58 \(\pm\) 4.10 & 21.58 \(\pm\) 2.05 \\ Redundant & 78.50-10 & 1062 & 74 & 1.03 \(\pm\) 1.27 & 13.49 \(\pm\) 4.26 & 4.28 \(\pm\) 1.56 & 3.96 \(\pm\) 1.24 & 21.60 \(\pm\) 1.24 \\ Potential & 78.50-10 & 1062 & 74 & 1.03 \(\pm\) 1.27 & 13.49 \(\pm\) 4.26 & 4.25 \(\pm\) 0.46 & 32.52 \(\pm\) 4.46 & 30.49 \(\pm\) 1.24 & 26.00 \(\pm\) 2.27 \\ Potential & 78.50-10 & 1062 & 74 & 1.03 \(\pm\) 1.27 & 13.49 \(\pm\) 4.26 & 4.26 \(\pm\) 0.46 & 23.25 \(\pm\) 4.46 & 30.49 \(\pm\) 1.24 & 26.00 \(\pm\) 2.27 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 5.70 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.85 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 5.70 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.85 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 5.87 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.85 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 38.10 \(\pm\) 6.57 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.95 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 6.38 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.95 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 6.38 & 20.68 \(\pm\) 6.79 & 88.39 \(\pm\) 5.72 & 88.95 \(\pm\) 3.54 & 24.00 \(\pm\) 3.16 \\ Phenol & 100.49-52.0 & 2000 & 94 & 37.53 \(\pm\) 2.95 & 31.20 \(\pm\) 6.38 & 20.68 \(\pm\) 6. Alcohols in fermented foods originate from the metabolism of sugars and amino acids during microbial fermentation. They are essential components that determine the flavor characteristics of BBP [49]. Compared to fermentation on day 7, the alcohol content in meju samples on day 35 significantly increased from 2673.02 \(\pm\) 158.77 ug/kg (L), 3981.63 \(\pm\) 32.83 ug/kg (M), and 2937.76 \(\pm\) 74.01 ug/kg (H) to 6620.24 \(\pm\) 189.14 ug/kg (L), 11,175.72 \(\pm\) 75.63 ug/kg (M), and 6637.19 \(\pm\) 226.84 ug/kg (H), respectively (Table 2, Figure 5B). 3-Methyl-1-butanol, 1-nonanol, 1-octen-3-ol, hepetaethylene glycol, and glycerol were the most abundant alcohols in the meju samples on day 35 (Table 2). Among them, 3-methyl-1-butanol and 1-octen-3-ol were the key aroma-active compounds in BBP [48]. By day 35, the contents in the three different meju were medium-salt > low-salt > high-salt. This result indicated that high-salt conditions inhibited the microbial growth associated with forming these two flavor compounds. 3-Methyl-1-butanol has a fatty aroma, while 1-octen-3-ol has a mushroom and fruity odor. Therefore, salt-reduced fermentation may contribute to the accumulation of these two flavors in BBP-meju. However, 2,3-butanediol has intense creamy and fruity aromas, which increase with increasing salt concentration. It was shown that a high-salt environment contributed to the formation and accumulation of specific high-quality flavors. Ethanol and fatty acids produced by microbial metabolism undergo esterification to generate ethyl acetate. Therefore, the higher level of ethanol in BBP-meju could explain the abundance of ethyl esters [40]. On the other hand, the esterification of fatty alcohols with acetic acid or the alcoholysis pathway with acetyl-CoA can generate acetate esters [50]. High levels of ethyl esters and acetate esters were detected in BBP-meju samples, including ethyl acetate, ethyl palmitate, ethyl phenylacetate, phenethyl acetate, ethyl isovalerate, isobutyl acetate, and isoamyl acetate (Table 2). These compounds together brought fruity, sweet, and floral flavors to BBP-meju. Additionally, they could mask the bitter and pungent odors due to the accumulation of fatty acid and amino acid [51].