## 2 Results and Discussion
### E-Nose and E-Tongue Analyses
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Attributes**} & \multicolumn{6}{c}{**Durian Cultivars**} \\ \cline{2-7}  & **Black Thorn** & **RSD * (\%)** & **Musang King** & **RSD (\%)** & **Monthong** & **RSD (\%)** \\ \hline Sugar (ug/mg) & & & & & & \\ Glucose & 10.49 & 1.1 & 34.26 & 1.90 & 30.91 & 1.46 \\ Frucose & 10.05 & 0.5 & 49.45 & 1.59 & 43.70 & 1.27 \\ Ribose & 0.69 & 5.03 & - & - & & \\ Sucrose & 235.34 & 0.89 & 111.53 & 1.17 & 57.26 & 0.96 \\ Malulose & 1.06 & 1.03 & 20.76 & 1.28 & 6.87 & 0.34 \\ Organic acid (mg/mg) & & & & & & \\ Propionic acid & 2210.56 & 4.99 & 1109.35 & 4.13 & 275.93 & 1.84 \\ Isoburicylic acid & 49.83 & 1.35 & 8.18 & 1.73 & 29.48 & 1.62 \\ Butyric acid & 117.97 & 2.51 & 77.01 & 3.13 & 49.84 & 2.91 \\ Oxalic acid & 798.03 & 2.42 & 263.26 & 1.59 & 389.03 & 1.49 \\ lactic acid & 34.22 & 4.46 & 41.64 & 0.64 & 369.25 & 2.97 \\ Valeric acid & 5.17 & 4.28 & 5.36 & 0.19 & 3.23 & 2.71 \\ Isovaleric acid & 87.38 & 4.08 & 26.75 & 0.69 & 30.24 & 4.22 \\ Malonic acid & 14.45 & 2.69 & 29.83 & 1.95 & 8.40 & 0.45 \\ Hexanoic Acid & 55.52 & 3.00 & 45.53 & 0.81 & 38.58 & 0.03 \\ 4-Methylvaleric Acid & 61.59 & 0.17 & 51.66 & 4.16 & 43.26 & 2.03 \\ Fumaracid & 260.76 & 2.06 & 444.80 & 1.17 & 281.58 & 1.40 \\ Maleic acid & 1316.30 & 3.83 & 2245.44 & 0.13 & 1420.47 & 4.87 \\ Succinic acid & 1143.95 & 3.10 & 8442.83 & 2.79 & 4681.37 & 0.26 \\ Benzoic acid & 4.23 & 0.76 & 10.10 & 3.41 & 6.75 & 0.86 \\ Itaconic acid & 1.06 & 3.37 & 0.15 & 4.09 & 0.25 & 0.17 \\ Glutaric Acid & 94.26 & 4.58 & 103.23 & 4.61 & 58.34 & 2.30 \\ Malic acid & 3888.95 & 0.48 & 5968.80 & 2.05 & 4180.52 & 3.70 \\ Salicylic acid & 1.04 & 4.43 & 0.82 & 4.81 & 0.67 & 2.53 \\ Octanoic Acid & 27.02 & 2.87 & 30.16 & 1.14 & 35.95 & 0.79 \\ Adpici acid & 42.66 & 0.87 & 202.74 & 0.98 & 24.35 & 0.32 \\ Tarratic acid & 72.44 & 1.57 & 125.45 & 1.19 & 221.67 & 4.27 \\ Pimelic Acid & 39.89 & 2.96 & 40.51 & 3.43 & 44.09 & 0.62 \\ Shikina Acid & 28.11 & 0.57 & 29.00 & 2.09 & 64.06 & 2.14 \\ Citric acid & 4857.13 & 2.58 & 1141.27 & 1.52 & 1897.57 & 0.55 \\ Isocitricacid & 212.97 & 0.12 & 47.38 & 5.62 & 72.81 & 3.86 \\ Quintic acid & 99.10 & 0.32 & 4.08 & 2.85 & 43.12 & 1.91 \\ Acetic acid & 2934.75 & 1.22 & 5490.22 & 4.12 & 3521.15 & 2.18 \\ Amino acids (mg/mg) & & & & & & \\ L-Alanine & 6451.55 & 2.45 & 3897.17 & 1.43 & 6019.09 & 3.94 \\ L-Arginine & 1526.99 & 1.55 & 1267.24 & 2.23 & 1108.34 & 1.63 \\ L-Asparagine & 65.71 & 3.62 & 39.83 & 1.97 & 42.86 & 3.73 \\ L-Asparagine & 6708.92 & 5.74 & 4634.31 & 2.47 & 3884.03 & 1.36 \\ L-Cyssteine & 87.47 & 3.61 & 104.66 & 2.29 & 63.88 & 0.66 \\ L-Glutamic acid & 3849.50 & 2.24 & 3462.46 & 0.34 & 3040.48 & 0.93 \\ L-Glutamic & 0.99 & 2.71 & 0.75 & 3.68 & 1.91 & 3.59 \\ Glycine & 1796.68 & 0.60 & 1617.87 & 0.44 & 1506.77 & 4.59 \\ L-Histidine & 615.19 & 4.47 & 520.96 & 1.53 & 460.74 & 4.86 \\ L-Isoucine & 1186.12 & 1.83 & 1189.70 & 3.01 & 1109.90 & 1.83 \\ L-Leucine & 2156.67 & 4.03 & 2137.24 & 1.64 & 1903.56 & 2.98 \\ L-Lysine & 1614.67 & 0.26 & 1446.72 & 0.92 & 1381.04 & 2.77 \\ L-Mehionine & 54.18 & 3.49 & 63.62 & 2.30 & 38.23 & 3.03 \\ L-Phenylalanine & 1454.20 & 4.51 & 1243.40 & 1.34 & 1093.01 & 1.76 \\ L-roline & 1699.47 & 0.72 & 1499.98 & 3.21 & 1440.28 & 0.12 \\ L-Serine & 1580.29 & 1.10 & 1390.38 & 1.87 & 1305.95 & 2.57 \\ L-Threonine & 1177.47 & 2.20 & 1130.76 & 1.71 & 1016.17 & 4.58 \\ L-Typtophan & & 0.15 & 4.26 & & & \\ L-tyrosine & 875.93 & 3.41 & 721.99 & 2.11 & 654.02 & 4.29 \\ L-Valine & 1524.03 & 3.46 & 1454.92 & 0.31 & 1354.35 & 2.19 \\ \hline \hline \end{tabular}  
* RSD, relative standard deviation.  
\end{table} 
Table 2: Sugar, organic acid, and amino acid contents of three durian cultivars. procedure. The higher the total variance, the more the principal component can reflect the information [34]. PCA results showed that the e-nose data were stable, and the three durians could be well separated. The values of the principal Component 1 of BT and MT were similar, which indicates that they had similar flavors. Figure 1: Radar map of electronic nose.