Open Access

Table 4

Changes in the tocopherol composition of pumpkin, melon and sunflower oils during microwave and conventional heating.

Tocopherols, % Control oils (0 min) Microwave heating Conventional heating   
    600W 900W
    3 min  6 min  9 min  12 min 3 min  6 min  9 min  12 min  9 min  12 min  18 min
Pumpkin seed oil             
   α-Tocopherol 5.6 ± 0.3b 6.7 ± 0.5a 6.4 ± 0.2a 5.9 ± 0.4b 5.4 ± 0.2b 7.5 ± 0.5c 8.3 ± 0.2c 7.0 ± 0.5d 4.2 ± 0.4e 5.7 ± 0.3b 4.2 ± 0.2f 2.8 ± 0.2g
   γ-Tocopherol 89.9 ± 1.0d 88.5 ± 0.8e 90.8 ± 0.5d 90.8 ± 0.7cd 90.8 ± 0.8c 87.1 ± 1.1e 88.5 ± 0.5d 89.5 ± 0.7cd 92.9 ± 0.5c 90.4 ± 0.9b 92.0 ± 0.5b 93.9 ± 0.6a
   γ-Tocotrienol 2.4 ± 0.4a 2.3 ± 0.1a 1.4 ± 0.2bc 2.0 ± 0.2ab 2.0 ± 0.3bc 2.5 ± 0.1a 1.6 ± 0.1bc 1.9 ± 0.3ab 1.0 ± 0.2bc 2.1 ± 0.1ac 1.7 ± 0.3bc 1.1 ± 0.1c
   δ-Tocopherol 2.1 ± 0.2b 2.5 ± 0.2a 1.4 ± 0.1c 1.3 ± 0.3c 1.8 ± 0.4bc 2.9 ± 0.2a 1.6 ± 0.2c 1.6 ± 0.1c 1.9 ± 0.3bc 1.8 ± 0.2c 2.1 ± 0.1bc 2.1 ± 0.1b
Melon seed oil             
   α-Tocopherol 10.2 ± 0.2a 8.7 ± 0.3bc 9.1 ± 0.1bc 8.7 ± 0.4bc 8.0 ± 0.5bc 8.6 ± 0.3c 8.2 ± 0.5c 8.2 ± 0.2c 8.4 ± 0.4c 8.7 ± 0.6b 9.5 ± 0.5b 9.3 ± 0.3b
   γ-Tocopherol 87.8 ± 1.0a 88.1 ± 0.5a 88.8 ± 0.8a 89.8 ± 0.6a 90.4 ± 1.1a 90.0 ± 0.9a 89.2 ± 1.2a 89.7 ± 0.9a 89.6 ± 0.8a 89.5 ± 0.5a 88.8 ± 0.7a 88.7 ± 0.6a
   γ-Tocotrienol 2.0 ± 0.4a 3.2 ± 0.2a 2.1 ± 0.1a 1.5 ± 0.1a 1.6 ± 0.2a 1.4 ± 0.1a 2.6 ± 0.4a 2.1 ± 0.1a 2.0 ± 0.2a 1.8 ± 0.3a 1.7 ± 0.2a 2.0 ± 0.1a
Sunflower oil             
   α-Tocopherol 96.0 ± 1.2a 94.2 ± 0.8ab 95.1 ± 1.0b 95.5 ± 0.5a 96.8 ± 0.8a 94.1 ± 0.7ab 91.1 ± 0.6b 95.6 ± 1.0a 97.0 ± 1.1a 96.4 ± 0.7a 94.6 ± 0.6a 91.1 ± 1.0c
   β-Tocopherol 4.0 ± 0.5d 5.8 ± 0.3f 4.9 ± 0.4e 4.5 ± 0.1d 3.2 ± 0.2d 5.9 ± 0.4c 8.9 ± 0.5b 4.4 ± 0.4d 3.0 ± 0.2d 3.6 ± 0.3d 5.4 ± 0.4d 8.9 ± 0.2a

Values are means ± SD (n = 3). Different letters in the same line mean significant differences (p ˂ 0.05) using Duncan test.

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