Effect of Thermal Treatments on Quality and Aroma of Watermelon Juice
Table 1
Volatiles detected in the watermelon juice.
Type
Volatiles
Unpasteurized (mg/L)
UHT (mg/L)
LTLT (mg/L)
HTST (mg/L)
Alcohol
2-Methyl-1-propanol
2.99 ± 0.18
-
-
-
3-Methyl-1-butanol
0.58 ± 0.04
-
-
-
Hexyl alcohol
2.78 ± 0.43
-
-
-
2-Octanol
3.13 ± 0.25
-
-
-
2-Ethylhexanol
1.10 ± 0.14
-
-
0.93 ± 0.32
(3Z)-3-Nonen-1-ol
10.3 ± 0.84
7.54 ± 1.20
9.37 ± 0.58
5.68 ± 1.20
(E)-2-Nonen-1-ol
13.0 ± 1.35
10.6 ± 0.87
10.9 ± 0.57
9.95 ± 0.51
Geraniol
0.75 ± 0.04
-
-
-
Phenethyl alcohol
9.19 ± 0.91
11.6 ± 0.59
-
-
1-Tridecanol
2.41 ± 0.14
26.3 ± 1.28
20.9 ± 1.59
15.8 ± 1.21
Dodecyl alcohol
0.58 ± 0.03
-
-
-
1-Tetradecanol
-
3.97 ± 0.64
3.16 ± 1.04
-
Subtotal
46.81
60.01
44.33
32.32
Aldehyde
2-Hexenal, (E)
13.0 ± 1.20
3.77 ± 0.25
11.8 ± 0.75
7.08 ± 0.72
Octanal
15.7 ± 1.39
10.2 ± 0.58
6.50 ± 0.74
13.25 ± 1.20
(E)-Hept-2-enal
3.68 ± 0.68
-
1.21 ± 0.24
-
1-Nonanal
25.4 ± 2.39
22.5 ± 1.55
23.7 ± 2.04
28.07 ± 0.87
Decyl aldehyde
18.3 ± 0.88
17.3 ± 1.24
4.29 ± 0.47
6.21 ± 0.49
(2E)-2-Nonenal
30.4 ± 2.89
24.3 ± 1.89
26.88 ± 1.47
29.38 ± 2.41
(E,Z)-2,6-Nonadienal
77.6 ± 5.21
60.5 ± 2.80
69.4 ± 4.24
66.1 ± 0.89
(E)-2-Dodecenal
23.0 ± 2.41
15.9 ± 1.14
20.7 ± 2.45
18.8 ± 2.08
Subtotal
207.08
154.47
164.48
168.89
Ketone
6-Methyl-5-hepten-2-one
11.92 ± 1.52
14.7 ± 1.22
7.57 ± 1.07
10.1 ± 0.88
6,10-Dimethyl-5,9-undecadien-2-one
8.50 ± 1.14
17.8 ± 1.38
26.8 ± 1.52
18.7 ± 0.58
2-Pentadecanone
0.99 ± 0.07
5.89 ± 0.38
8.09 ± 1.03
7.89 ± 0.74
Subtotal
21.41
38.36
42.46
36.69
Acid
Acetic acid
-
8.27 ± 1.71
3.65 ± 0.28
11.17 ± 1.51
2-Methyl butyric acid
-
1.04 ± 0.17
0.67 ± 0.02
2.41 ± 0.18
Octanoic acid
-
6.09 ± 0.47
0.64 ± 0.09
9.80 ± 1.42
Subtotal
0
15.4
4.96
23.38
Ester
Octyl formate
-
-
-
2.38±
Diisobutyl phthalate
0.78 ± 0.03
7.05 ± 0.71
9.54 ± 0.85
9.16 ± 0.17
Isopropyl palmitate
-
2.52 ± 0.21
0.73 ± 0.03
2.41 ± 0.17
Subtotal
0.78
9.57
10.27
13.95
Other
Tetradecane
1.94 ± 0.17
-
8.41 ± 1.30
-
1-Hexadecene
2.09 ± 0.28
-
-
-
2-Pentylfuran
9.25 ± 0.84
12.1 ± 0.98
15.0 ± 1.17
14.9 ± 1.07
Phenol
0.84 ± 0.04
-
-
-
Subtotal
14.12
12.1
23.41
14.9
-: not detected; : significant difference with the unpasteurized juice at ;: significant difference with the unpasteurized juice at ; typical volatiles of watermelon; UHT: ultrahigh temperature; LTLT: low temperature long time; HTST: high temperature short time.
