Table 2.
Quality characteristics of different vegetable oils before, after 5th and 10th consecutive frying sessions
| Types of vegetable oil | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||
| Red palm oil | Yellow palm oil | Corn oil | |||||||
|
|
|
|
|||||||
| Before frying | After 5th frying | After 10th frying | Before frying | After 5th frying | After 10th frying | Before frying | After 5th frying | After 10th frying | |
| Peroxide value, meq kg−1 oil | 7.12a(0.29) | 12.5b(0.19) | 12.9b(0.46) | 7.09a′(0.22) | 12.4b′(1.16) | 13b′(0.52) | 8.81a″(0.13) | 9.13a″(0.04) | 9.53b″(0.07) |
| Iodine value, g of I 100 g−1 oil | 92.9a(1.43) | 88.2b(0.59) | 83.7b(1.05) | 64.8a′(0.08) | 56.9b′(0.07) | 54.5c′(0.42) | 93.3a″(0.09) | 92.8a″(0.18) | 85.3b″(0.91) |
| p-Anisidine value | 6.61a(0.33) | 10.7b(0.32) | 12.8c(0.16) | 2.33a′(0.06) | 4.17b′(0.13) | 9.19c′(0.13) | 3.92a″(0.07) | 6.42b″(0.09) | 10.7c″(0.11) |
| Free fatty acids, % | 0.09a(0.014) | 0.15b(0.006) | 0.21c(0.006) | 0.09a′(0.003) | 0.11a′(0.003) | 0.11a′(0.004) | 0.12a″(0.014) | 0.13a″(0.014) | 0.13a″(0.021) |
| TOTOX value, 2 PV+AV | 20.6a(1.97) | 35.5b(1.55) | 38.5c(0.54) | 16.5a′(3.04) | 28.9b′(7.89) | 35.2c′(0.98) | 21.8a″(4.56) | 24.7b″(0.66) | 29.7b″(3.63) |
| Fatty acid distribution, % | |||||||||
| Saturated fatty acid | 48.0a (0.47) | 49.5a(0.51) | 51.9b(0.26) | 38.6a′(0.38) | 40b′(0.07) | 41.2c′(0.05) | 14.3a″(0.04) | 14.8b″(0.09) | 15.2c″(0.15) |
| Monounsaturated fatty acid | 33.5a(0.12) | 34b(0.01) | 34.3c(0.05) | 35.1a′(0.13) | 35.5a′(0.42) | 35.9a′(0.07) | 10.9a″(0.03) | 11.7b″(0.10) | 19c″(0.10) |
| Polyunsaturated fatty acid | 19.9a(0.06) | 16.6b(0.42) | 13.5c(0.70) | 25.4a′(0.78) | 23.4ab′(0.18) | 21.4b′(0.11) | 74.1a″(0.30) | 73.2a″(0.15) | 66.6b″(0.33) |
a–c
Values within the same row with different letters among different treatments using red palm oil are significantly different (P ≤ 0.05)
a′–c′
Values within the same row with different letters among different treatments using yellow palm oil are significantly different (P ≤ 0.05)
a″–c″
Values within the same row with different letters among different treatments using corn oil are significantly different (P ≤ 0.05)
Values are means of duplicate determination (±SD)