Table 2.
Regression equations from variations in oxidative indices during accelerated storage of raw and roasted hazelnuts
| T (°C) | Hazelnut type | Regression equation | k (1/day) | Temperature effect on k | Effect of treatment on k | r2 |
|---|---|---|---|---|---|---|
| Peroxide value (mEq O2/kg) | ||||||
| 55 |
Raw Roasted |
Y = 0.1314x + 0.223 Y = 0.9358x − 4.3662 |
0.1314bc 0.9358b |
0.705b |
0.412b 1.643a |
0.99 0.91 |
| 65 |
Raw Roasted |
Y = 0.2477x + 0.4601 Y = 1.7948x − 2.7409 |
0.2477c 1.7948a |
1.021ab |
0.412b 1.643a |
0.98 0.97 |
| 75 |
Raw Roasted |
Y = 0.4606x + 0.7567 Y = 2.2604x + 1.0895 |
0.4606bc 2.2604a |
1.356a |
0.412b 1.643a |
0.94 0.95 |
| < 0.0001 | 0.0262 | 0.0001 | ||||
| Para-anisidine value (100 times the specific absorbance at 350 nm) | ||||||
| 55 |
Raw Roasted |
Y = 0.028x + 0.1877 Y = 0.8211x − 1.2213 |
0.028d 0.8211c |
0.174c |
0.051b 0.671a |
0.95 0.94 |
| 65 |
Raw Roasted |
Y = 0.0453x + 0.1204 Y = 0.6272x − 0.9173 |
0.0453d 0.6272b |
0.336b |
0.051b 0.671a |
0.98 0.98 |
| 75 |
Raw Roasted |
Y = 0.081x + 0.2043 Y = 1.0673x − 0.8937 |
0.081d 1.0673a |
0.574a |
0.051b 0.671a |
0.99 0.94 |
| < 0.0001 | < 0.0001 | < 0.0001 | ||||
| TOTOX value (2PV + p-AnV) | ||||||
| 55 |
Raw Roasted |
Y = 0.2516x + 1.0915 Y = 2.1928x − 9.9537 |
0.2516f 2.1928c |
1.175c |
0.598b 3.962a |
0.97 0.92 |
| 65 |
Raw Roasted |
Y = 0.5406x + 1.0405 Y = 4.2168x − 6.3992 |
0.5406e 4.2168b |
2.378b |
0.598b 3.962a |
0.98 0.98 |
| 75 |
Raw Roasted |
Y = 1.0023x + 1.7176 Y = 5.5965x + 1.2674 |
1.0023d 5.5965a |
3.286a |
0.598b 3.962a |
0.95 0.97 |
| < 0.0001 | < 0.0001 | < 0.0001 |
Values in vertical columns with different letters are significantly different (P < 0.05)