Fig. 1:
Mango leaf sample in twig (a) The position of five leaves on the twig, (b) the five samples with symbols d1, d2, d3, d4 and d5.
Fig. 2:
Approximation structure model. (a) The anatomical structure of a fruits and vegetables [18], (b) Hayden equivalent electrical circuit [18], (c) double-shell equivalent electrical circuit [19].
Fig. 3:
Design of sample impedance measurement. (a) the scheme measurement, (b) the impedance process measurement with the Analog Discovery 2 and the result displayed on computer.
Fig. 4:
The modified double-shell equivalent electrical circuit.
Fig. 5:
The Nyquist plot in six samples with fitting plot; (a) Gadung; (b) Manalagi; (c) Golek; (d) Janis; (e) Podang; (f) Apel.
Table 1.
Spearman’s correlation analysis.
| No | Mango Variety | C1 | R1 | n1 | |||
|---|---|---|---|---|---|---|---|
| ρ | p-value | ρ | p-value | ρ | p-value | ||
| 1 | Manalagi | −1.0 | - | 0.9 | 0.037 | 0.1 | 0.872 |
| 2 | Gadung | −0.5 | 0.391 | 1.0 | - | −0.6 | 0.284 |
| 3 | Janis | −1.0 | - | 0.1 | 0.873 | 0.5 | 0.391 |
| 4 | Apel | −1.0 | - | 0.9 | 0.037 | 0.8 | 0.104 |
| 5 | Podang | −1.0 | - | 1.0 | - | 0.6 | 0.284 |
| 6 | Golek | −1.0 | - | 0.9 | 0.037 | 0.8 | 0.104 |
Fig. 6.
Linear regression of C1.
Fig. 7.
Linear regression of R1.
Table 2.
Regression parameters of C1.
| Variety | a (intercept) | b (slope) | R2 |
|---|---|---|---|
| Gadung | 2.11E-10 ± 2.76E-11 | -5.54E-12 ± 3.66E-12 | 0.434 |
| Manalagi | 2.01E-10 ± 1.43E-11 | -1.10E-11 ± 1.89E-12 | 0.918 |
| Golek | 1.41E-10 ± 1.05E-11 | -3.34E-12 ± 1.39E-12 | 0.657 |
| Janis | 1.79E-10 ± 7.17E-13 | -6.41E-12 ± 9.50E-14 | 0.999 |
| Podang | 3.97E-10 ± 3.52E-11 | -2.78E-11 ± 4.66E-12 | 0.921 |
| Apel | 1.46E-10 ± 3.49E-12 | -6.44E-12 ± 4.63E-13 | 0.984 |
Table 3.
Regression parameters of R1.
| Variety | a (intercept) | b (slope) | R2 |
|---|---|---|---|
| Gadung | 82064.5 ± 4311.54 | 4311.5 ± 571.08 | 0.949 |
| Manalagi | 88630.0 ± 10984.68 | 7790.0 ± 1454.95 | 0.909 |
| Golek | 104355.0 ± 14714.80 | 7875.0 ± 1949.02 | 0.844 |
| Janis | 109730.0 ± 11997.19 | 1030.0 ± 1589.06 | 0.123 |
| Podang | −6070.5 ± 2528.24 | 16415.5 ± 3348.76 | 0.889 |
| Apel | 171435 ± 23819.12 | 6915.0 ± 3154.92 | 0.616 |