# Volatile Compounds, Sensory Profile and Phenolic Compounds in Fermented Rice Bran
## 2 Results
### Volatile Compounds of Rice Bran  
The volatile compounds of fermented and non-fermented RB of IPR30 and CI were shown in Table 2. The 55 identified volatile compounds consisted of 13 alcohols, 11 aldehydes, 6 acids, 5 ketones, 4 phenols, 4 esters, 2 benzene, 3 terpenes, 2 furans, 2 lactones, 1 pyridine, 1 pyrazine, and 1 thiazole. The alcohol compounds were the most volatile compounds that were detected in both RB varieties (fermented and non-fermented), followed by aldehydes, acids, ketones, phenols, esters, benzenes, terpenes, furans, pyridines, and thiazole (Figure 1).  
The present study applied principal component analysis (PCA) to compare the differences and identify dominant volatile compounds among the fermented and non-fermented RB. The PCA plot of volatile compounds in Figure 2 shows RB with fermentation and without fermentation located in different dimensions. It shows that the fermentation process can affect the volatile compounds of RB.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Incubation** & \multicolumn{2}{c}{**IPR30**} & \multicolumn{2}{c}{**CI**} \\ \cline{2-4}
**Time (h)** & **TPC** & **DPPH RSA** & **TPC** & **DPPH RSA** \\ \hline
0 & 1.57 \(\pm\) 0.19 a  & 0.94 \(\pm\) 0.13 a  & 6.12 \(\pm\) 0.70 a  & 9.22 \(\pm\) 0.77 a  \\
48 & 1.96 \(\pm\) 0.02 ab  & 1.21 \(\pm\) 0.66 b  & 6.10 \(\pm\) 0.53 a  & 5.27 \(\pm\) 0.03 b  \\
72 & 2.24 \(\pm\) 0.21 b  & 1.46 \(\pm\) 0.14 b  & 7.85 \(\pm\) 0.61 b  & 10.37 \(\pm\) 0.82 ac  \\
96 & 2.18 \(\pm\) 0.28 b  & 1.80 \(\pm\) 0.05 c  & 7.34 \(\pm\) 0.72 b  & 11.74 \(\pm\) 0.84 c [FONOTE:c]Footnote c: footnotemark: [ENDFOOTNOTE] \\ \hline \hline \end{tabular}  
* TPC are expressed as [mg of gallic acid equivalents (GAE)/g DB and DPPH radical scavenging activity (RSA) are expressed as mg Trolox equivalent (TE) per 100 g of sample DB. Values are given as the means \(\pm\) SD, n = 4. Means with the different letters within column are significantly different (\(\
u\) < 0.05) followed by [PERSON]’s multiple range test.  
\end{table}
Table 1: Total phenolic content (TPC) and DPPH radical scavenging activity (RSA) of RB.  
Figure 1: Groups of volatile compounds in fermented or non-fermented rice bras. Inpari 30 non-fermented (IPR30 NF); Inpari 30 fermented (IPR30F); Cempo Ireng non fermented (CINF); and Cempo Ireng fermented (CIF).  
Volatile compounds of IPR30 fermented RB were dominated by 3-methylbut-3-en-1-ol; 2,3-butandiol; benzylalcohol; glycerin; methyl hexadecanoate; (E)-9-methyl octadecanoate; (Z, Z) -9,12-methyl octadecadienoate; 1R-alpha-pinene; cyanophyllene; 2-methoxyphenol; and 3-methyl pyridine. Most of these compounds were formed from lipid oxidation through enzymes activity in the mold that was used as the starter of fermentation. During the sterilization process in preparation of RB before fermentation, 2-Methoxyphenol and 3-methylpyridine were formed as a product of the Maillard reaction. These compounds contributed to sweaty, creamy, fatty, pungent, and smoky aromas. Conversely, IPR30 non-fermented RB was dominated by 2-furanmetanol; nonanal; methyl tetradecanoate; phenol; and 4-ethenyl-2-methoxyphenylenol (Figure 2a). These compounds contributed to burnt, nutty, and fatty aromas.  
Meanwhile, the volatile compounds of CI fermented RB were dominated by 4-methyl-3-penten-1-ol; benzyl alcohol; glycerin; methyl hexadecanoate; ethylbenzene; and cyanophyllene. Most of these compounds were formed by hydrolysis of fatty acids in RB through enzyme activity in the mold that was used as the starter for fermentation. Furthermore, CI non-fermented RB was dominated by 2-furanmetanol; hexanal; naphthalene; 1R-alpha-pinene; and 4-ethenyl-2-methoxyphenol (Figure 2b) that contributed to burnt, nutty, fatty, and pungent aromas.