# Characterization of the Aroma of an Instant White Tea Dried by Freeze Drying
## 2 Results and Discussion
### GC-MS Analysis of Volatile Compounds in SDE Extract of IWT
\begin{table}
\begin{tabular}{l l c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Volatile**} & \multicolumn{3}{c}{**RTX-5 MS**} & \multicolumn{3}{c}{**RTX-WAX**} & \multicolumn{3}{c}{**Characteristic**} & \multirow{2}{*}{**Reference**} & \multirow{2}{*}{**Standard Curve/**} & \multirow{2}{*}{**R2**} & \multirow{2}{*}{**Range**} & \multirow{2}{*}{**CF**} & \multirow{2}{*}{**(mfg/L)**} \\ \cline{3-3} \cline{8-11}  & & **R1\({}^{\star}\)** & & & & & & & & & & & & \\ \hline \multicolumn{11}{c}{} & alcohols & & & & & & & & & & & & & & \\ \(1\) & 3-head & - & - & 797 & - & 1211 & 56 \# 984 & Std MS & Y = 1.1043X \(-\) 0.0868 & 0.9906 & 0.1–10 & 0.732 & 2.7 \(\pm\) 0.6 \\ \(2\) & benzyl alcohol & 106 & 1037 & 1847 & 180 \# 170 & Std MS & Y = 1.0963X \(-\) 0.4311 & 0.9970 & 0.5-200 & 0.541 & 19.7\(\pm\) 9.7 \\ \(3\) & linlool & 1100 & 1100 & 1592 & 1582 & 7.41 \# 139 & Std MS & Y = 2.2928X \(-\) 0.1747 & 0.9996 & 0.5-200 & 0.441 & 128.7 \(\pm\) 3.4 \\ \(4\) & Hoitreul \(1\) & 1105 & 1107 & - & 1623 & 7.81 \# 343 & MS & N & internal standard method & & & & \\ \(5\) & 3-octn-2-1 & 1108 & 1150 & 1390 & 31.9 \# 110 & Std MS & Y = 3.6322X \(-\) 0.2884 & 0.9991 & 0.5-100 & 0.277 & 3.3 \(\pm\) 0.0 \\ \(6\) & phenylethyl alcohol & 1114 & 1114 & 1507 & 1912 & 91 \# 122 & Std MS & Y = 7.6317X \(-\) 0.5345 & 0.9995 & 0.5-100 & 0.132 & 19.4 \(\pm\) 1.1 \\ \(7\) & a-terphenyl & 1129 & 11969 & 1692 & 99.9 \# 3121 & Std MS & Y = 1.2469X \(-\) 0.0785 & 0.9994 & 0.5-100 & 0.808 & 63.0 \(\pm\) 2.1 \\ \(8\) & gramani & 1259 & 1260 & 1854 & 1854 & 9.61 \# 684 & Std MS & Y = 1.6663X \(-\) 0.8133 & 0.9994 & 0.5-100 & 0.803 & 60.4 \(\pm\) 4.5 \\ \(9\) & 2-4-ditert-butylphenol & 1516 & 1513 & - & 2231 & 191 \# 276 & Std MS & Y = 17.5469X \(+\) 0.1502 & 0.9998 & 0.1–10 & 0.057 & 0.2 \(\pm\) 0.1 \\ \(10\) & control & 1648 & 1608 & - & 2112 & 95 \# 150 151 & Std MS & Y = 1.1583X\(-\) 0.0940 & 0.9995 & 0.5–100 & 0.867 & 1.0 \(\pm\) 0.0 \\ \hline \multicolumn{11}{c}{} & aldehydes & & & & & & & & & & & \\ \(1\) & beneneenealdehyde & 1044 & 1044 & 1628 & 1626 & 91 \# 210 & Std MS & Y = 1.3974X \(-\) 0.0543 & 0.9995 & 0.5–100 & 0.719 & 38.0 \(\pm\) 2.2 \\ \(2\) & safran & 1201 & 1201 & 1631 & 1648 & 107 \# 121 & Std MS & Y = 2.6516X\(-\) 0.0499 & 0.9998 & 0.5–100 & 0.378 & 5.0 \(\pm\) 0.2 \\ \hline \multicolumn{11}{c}{} & ketones & & & & & & & & & & \\ \(1\) & 2-hexanne & - & 792 & - & 1098 & 43 \# 587 & Std MS & Y = 0.2404X\(-\) 0.2821 & 0.9990 & 0.5–100 & 0.264 & 31.4 \(\pm\) 2.9 \\ \(2\) & _trans_-g-dansconceme_ & 1387 & 1386 & 1380 & 1180 & 1107 \# 694 & Std MS & Y = 1.3020X\(-\) 0.0799 & 0.9998 & 0.5–100 & 0.725 & 5.9 \(\pm\) 0.2 \\ \(3\) & _trans_-g-inone & 1690 & 1490 & 1930 & 1925 & 177 \# 431 & Std MS & Y =In addition, the SDE extract seems to have higher content of geraniol, benzeneacetaldehyde and coumarin than the content of white teas reported by previous researches [20; 26]. Geraniol and linalool are synthesized in tea leaves from the geranyl pyrophosphate (GPP) via the catalysis by terpene synthases (TPS) [18]. Benzeneacetaldehyde and coumarin are important derivatives of phenylalanine produced via the oxidation in tea leaves [18; 27]. Tea infusions that are prepared with hot water from leaves have dramatically high contents of alcoholic volatiles such as geraniol [28], due to the thermal hydrolysis of glycosides precursors [18]. Heating during tea and instant tea processing may accelerate the oxidative degradation of phenylalanine [29], leading to higher contents of benzeneacetaldehyde and coumarin. Thus, the high content of geraniol, benzeneacetaldehyde and coumarin in the SDE extract could be attributed to the hydrolysis of glycosides precursors and oxidative degradation of phenylalanine caused by the heating during instant tea processing.