Table 9.
Overview of NIR Results for Leaf vegetables.
| Sample | Investigated Parameter | Concentration Range | Chemometrics Data | Ref. | ||
|---|---|---|---|---|---|---|
| Pre-Processing, Regression | R2 | Root Mean Square Error | ||||
| Spinach | Dry matter, % | 7.35–18.83 | SNV, DT, 2nd der., MPLS | 0.70 | 1.58 | [271] |
| 4.10–19.12 | SNV, DT, 1st der., 2nd der., MPLS | 0.66 | 1.22 | [272] | ||
| 6.12–20.34 | SNV, DT, 1st der., 2nd der., MPLS | 0.68 | 1.27 | [274] | ||
| Texture | ||||||
| Maximum puncture force, N | 0.37–4.51 | SNV, DT, 2nd der., MPLS | 0.62 | 0.83 | [271] | |
| 1.03–4.57 | SNV, DT, 1st der., 2nd der., MPLS | 0.3 | 0.41 | [272] | ||
| Tughness, mJ | 0.38–8.73 | SNV, DT, 2nd der., MPLS | 0.63 | 1.50 | [271] | |
| Stiffness, N/mm | 009–1.03 | SNV, DT, 2nd der., MPLS | 0.65 | 0.20 | ||
| Displacement, mm | 0.57–6.05 | SNV, DT, 2nd der., MPLS | 0.50 | 1.2 | ||
| Colour | ||||||
| a* | −17.32–(−10.78) | SNV, DT, 2nd der., MPLS | 0.31 | 1.09 | [271] | |
| b* | 13.77–23.02 | SNV, DT, 1st der., MPLS | 0.13 | 2.22 | ||
| Soluble solids content—SSC; °Brix | 5.6–14.25 | SNV, DT, 2nd der., MPLS | 0.86 | 0.59 | [77] | |
| 4.10–11.45 | SNV, DT, 2nd der., MPLS | 0.80 | 0.67 | [272] | ||
| 5.8–14.4 | SNV, DT, 1st der. 2nd der., PCA, PLS | 0.62 | 1.0 | [274] | ||
| 5.2–15.2 | SNV, DT, 1st der., 2nd der., MPLS | 0.68 | 1.0 | [273] | ||
| Ascorbic acid, mg/100 g | 157–454 | SNV, DT, 1st der., MPLS | 0.25 | 55.19 | [77] | |
| Nitrate content, mg/kg | 109–5177 | SNV, DT, 2nd der., MPLS | 0.41 | 834.27 | ||
| 41–3526 | SNV, DT, 1st der., 2nd der., PLS | 0.59 | 725 | [274] | ||
| 67–3844 | SNV, DT, 1st der., MPLS | 0.51 | 567.79 | [272] | ||
| 70–3875 | SNV, DT, 1st der., 2nd der., MPLS | 0.62 | 688 | [273] | ||
| 41–3845 | SNV, DT, MPLS | 0.45 | 920 | [275] | ||
| 623–3845 | SNV, DT, LOCAL | 0.60 | 758 | |||
| Microbiological spoilage, log CFU/g | 6.8–9.0 | random data partitioning, SVR | 0.4 | 0.6 | [276] | |
| Lettuce | Pigments | 5.0–8.5 | DT, PLS | 0.8 | 0.495 | [277] |
| Chlorophyll, mg/kg | ||||||
| Total carotenoid, mg/kg | 0.9–1.8 | 0.76 | 0.105 | |||
| Anthocyanins, mg/kg | 0.1–4.0 | 0.89 | 0.592 | |||
| Nitrate content, mg/kg fresh w. | 1200–2750 | SNV, MSC, PLS | 0.90 | 99.4 | [278] | |
| Classification | variety types | LDA | ||||
| red and green leaved variants of lollo and oak leaf variety types | LDA | AC 100%; PRE 100% | ||||
| organic and no-organic | SG, LDA | AC 96.4% (leaf); 96.9% (stem) | [279] | |||
| SS/RF/ANOVA, GA-LDA | AC 92.1/84.9/80.5% | |||||
| Potassium, mg/100 g | 165–480 | 1st der., CARS, PLS | 0.83 | 39.7 | [291] | |
| Green leaves (mixed samples) | 1st der., RBF-NN | 0.86 | 38.06 | |||
| Petioles (mixed samples) | CARS, PLS | 0.71 | 31.20 | |||
| RBF-NN | 0.88 | 27.63 | ||||
| Pesticide residues | n.i. | SGS, SNV, CARS-IRIV-SGS, SNV, GSA-SVM | AC = 98.33% | [280] | ||
| Biological investigations | n.i. | ANOVA, HSI | AC 97% (Vis-NIR), 100% (NIR) | [281] | ||
| Worms | ||||||
| Escherichia coli | SNV + 2nd der., PLS-DA | 0.958 | 0.257 | [282] | ||
| 0.1, 0.2, 0.3 mL | SVM | AC = 100% | ||||