Table 2.
PLS analysis results for predicting the AV and TPC values of frying oil samples.
| F | R 2 cal | SEC | SECV | R 2 val | SEP | Bias | RPD | ||
|---|---|---|---|---|---|---|---|---|---|
| AV | Raw spectra | 5 | 0.99 | 0.20 | 0.22 | 0.99 | 0.22 | 0.03 | 9.2 |
| First derivative spectra | 5 | 0.99 | 0.15 | 0.17 | 0.99 | 0.16 | 0.03 | 13.0 | |
| Second derivative spectra | 6 | 0.99 | 0.14 | 0.16 | 0.99 | 0.16 | 0.03 | 12.7 | |
|
| |||||||||
| TPC | Raw spectra | 6 | 0.98 | 1.13 | 1.26 | 0.98 | 1.13 | 0.00 | 7.1 |
| First derivative spectra | 6 | 0.98 | 1.04 | 1.16 | 0.98 | 1.10 | −0.09 | 7.3 | |
| Second derivative spectra | 6 | 0.98 | 1.05 | 1.17 | 0.98 | 1.10 | −0.01 | 7.3 | |
F: number of factors; R 2: coefficient of determination; SEC: standard error of calibration; SECV: standard error of cross validation; SEP: standard error of prediction; bias: average of differences between reference value and NIR value; RPD: ratio of standard deviation of reference data in the validation set to SEP.