Table 2.
Influence of thermal treatment and storage on tocopherol concentrations, peroxide, and acid values of untreated and UVB-exposeda wheat germ oil.
| Exposure | Treatment | Tocopherols (mg/100 g) |
Peroxide value (mEq O2/kg) | Acid value (g KOH/kg) | ||
|---|---|---|---|---|---|---|
| α | β | γ | ||||
| – | – | 165 | 62.9 | 8.1 | 7.0 | 10.3 |
| UVB | – | 166 | 64.3 | 8.2 | 5.0 | 10.4 |
| – | 100°C, 10 min | 164 | 63.2 | 8.3 | 8.8 | 9.8 |
| UVB | 100°C, 10 min | 163 | 63.8 | 8.1 | 7.1 | 10.8 |
| – | 180°C, 10 min | 159 | 59.3 | 7.7 | 1.0 | 10.2 |
| UVB | 180°C, 10 min | 160 | 59.5 | 7.7 | 1.0 | 9.5 |
| – | 1 day storage (RT) | 166 | 65.0 | 8.2 | n. a. | n. a. |
| UVB | 1 day storage (RT) | 166 | 63.8 | 8.1 | n. a. | n. a. |
| – | 2 weeks storage (RT) | 178 | 68.0 | 8.5 | n. a. | n. a. |
| UVB | 2 weeks storage (RT) | 163 | 63.0 | 7.9 | n. a. | n. a. |
| – | 4 weeks storage (RT) | 163 | 63.4 | 8.1 | 20.6 | 10.0 |
| UVB | 4 weeks storage (RT) | 160 | 61.8 | 7.8 | 21.4 | 10.1 |
aUVB exposure conditions: exposure time, 10 min; oil layer thickness, 1.6 mm; UVB lamp distance, 13 cm.
n. a., not analyzed; RT, room temperature.