# Prediction of Phytochemical Constituents in Cayenne Pepper Using MIR and NIR Spectroscopy
## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Pre-Processing**} & \multirow{2}{*}{**Analyte**} & \multirow{2}{*}{**LVs (PLS)**} & \multicolumn{2}{c}{**R\({}^{2}\)\({}_{\text{cal}}\)**} & \multicolumn{2}{c}{**RMSEC**} & \multicolumn{2}{c}{**R\({}^{2}\)\({}_{\text{pred}}\)**} & \multicolumn{2}{c}{**RMSEP**} & \multicolumn{2}{c}{**RPD**} \\ \cline{3-13}  & & & **PLS** & **SVR** & **PLS** & **SVR** & **PLS** & **SVR** & **PLS** & **SVR** & **PLS** & **SVR** \\ \hline None & DM & 16 & 0.69 & 0.93 & 0.492 & 0.245 & 0.60 & 0.12 & 0.467 & 0.734 & 1.661 & 1.057 \\  & TPC & 9 & 0.38 & 0.8 & 138.715 & 89.122 & 0.00 & 0.00 & 444.826 & 504.43 & 1.022 & 0.901 \\  & FRAP & 8 & 0.46 & 0.72 & 53.613 & 48.173 & 0.00 & 0.10 & 72.669 & 155 & 0.746 & 0.350 \\  & CUPRAC & 4 & 0.44 & 0.94 & 264.692 & 93.514 & 0.20 & 0.10 & 377.131 & 463.964 & 1.148 & 0.933 \\ \hline SG1 & DM & 12 & 0.63 & 0.99 & 0.54 & 0.005 & 0.40 & 0.46 & 0.58 & 0.806 & 1.337 & 0.962 \\  & TPC & 10 & 0.38 & 0.99 & 138.302 & 0.638 & 0.02 & 0.00 & 442.631 & 519.086 & 1.027 & 0.876 \\  & FRAP & 11 & 0.45 & 0.99 & 53.811 & 3.966 & 0.00 & 0.02 & 68.738 & 71.269 & 0.788 & 0.760 \\  & CUPRAC & 2 & 0.49 & 0.99 & 253.393 & 9.41 & 0.10 & 0.35 & 378.035 & 576.296 & 1.145 & 0.751 \\ \hline SG2 & DM & 12 & 0.61 & 0.98 & 0.549 & 0.138 & 0.49 & 0.22 & 0.539 & 0.96 & 1.439 & 0.808 \\  & TPC & 11 & 0.46 & 0.98 & 128.641 & 23.998 & 0.03 & 0.00 & 437.273 & 482.028 & 1.040 & 0.943 \\  & FRAP & 9 & 0.38 & 0.96 & 216.228 & 14.408 & 0.00 & 0.10 & 65.005 & 79.026 & 0.834 & 0.686 \\  & CUPRAC & 5 & 0.63 & 0.94 & 0.576 & 85.739 & 0.10 & 0.51 & 400.408 & 517.878 & 1.081 & 0.836 \\ \hline SNV & DM & 11 & 0.57 & 0.82 & 131.545 & 0.467 & 0.48 & 0.23 & 0.546 & 1.173 & 1.420 & 0.661 \\  & TPC & 10 & 0.44 & 0.57 & 60.258 & 138.805 & 0.02 & 0.00 & 437.747 & 451.948 & 1.038 & 1.006 \\  & FRAP & 7 & 0.31 & 0.77 & 202.685 & 36.318 & 0.00 & 0.77 & 69.791 & 67.445 & 0.776 & 0.803 \\  & CUPRAC & 10 & 0.67 & 0.84 & 0.521 & 147.952 & 0.10 & 0.55 & 404.968 & 466.772 & 1.069 & 0.927 \\ \hline SNV Detrend 1 & DM & 12 & 0.65 & 0.92 & 132.309 & 0.267 & 0.55 & 0.27 & 0.505 & 0.949 & 1.536 & 0.817 \\  & TPC & 10 & 0.43 & 0.74 & 46.033 & 95.437 & 0.03 & 0.69 & 436.035 & 44.868 & 1.043 & 1.070 \\  & FRAP & 14 & 0.6 & 0.86 & 204.903 & 29.065 & 0.00 & 0.35 & 68.737 & 73.335 & 0.788 & 0.739 \\  & CUPRAC & 10 & 0.67 & 0.84 & 0.514 & 164.865 & 0.10 & 0.14 & 406.269 & 379.48 & 1.141 & 1.066 \\ \hline SNV Detrend 2 & DM & 12 & 0.66 & 0.94 & 131.038 & 0.215 & 0.61 & 0.36 & 0.471 & 0.835 & 1.646 & 0.929 \\  & TPC & 10 & 0.44 & 0.74 & 60.769 & 95.629 & 0.04 & 0.52 & 433.938 & 433.212 & 1.048 & 1.049 \\  & FRAP & 7 & 0.44 & 0.81 & 203.345 & 35.055 & 0.00 & 0.1 & 69.287 & 66.516 & 0.782 & 0.815 \\  & CUPRAC & 10 & 0.67 & 0.86 & 0.574 & 138.588 & 0.10 & 0.22 & 400.107 & 435.655 & 1.082 & 0.994 \\ \hline MSC & DM & 10 & 0.58 & 0.82 & 132.335 & 0.452 & 0.48 & 0.21 & 0.544 & 1.098 & 1.426 & 0.706 \\  & TPC & 10 & 0.43 & 0.81 & 60.288 & 79.788 & 0.02 & 0.00 & 438.065 & 440.913 & 1.038 & 1.031 \\  & FRAP & 7 & 0.31 & 0.74 However, [PERSON] et al. [6] used a high-resolution laboratory-based NIR instrument (FOSS NIRSystems; 400-2500 nm) with the spectra collected from freeze-dried chili powder. Furthermore, an external validation set was used in the present study rather than just cross-validation against the calibration samples. This likely contributes further to the lack of predictive power for TP content and highlights the challenges of detecting phenolics in fresh chilies. It is likely that high levels of moisture content could interfere with and obscure the absorption bands of this analyte. In addition, [PERSON] et al. [6] found minimal loading of peaks in the short-wave NIR region in their TP content model, indicating that phenolic compounds may not show strong absorption across the range of wavelengths included in this study (908-1676 nm). Similarly, the best models for FRAP and CUPRAC had an RMSEP of 46 mg/100 g (RPD = 1.17) and an RMSEP of 379 mg/100 g (RPD = 1.07), respectively.