Table 1.
Effect of UV-C treatment and postharvest storage conditions on TPC, TFC, CAT, SOD and POD enzymatic activities and antioxidant capacity (DPPH and ABTS inhibition %) of papaya fruit
| Variable | Tissue | Treatment | Storage temperature (°C) | Storage period (days) | |||
|---|---|---|---|---|---|---|---|
| 0 | 5 | 10 | 15 | ||||
| TPC (mg GA *100 gfw−1) | Peel | Control | 5 | 257.6±5.3 | 233.0x,a | 219.4y,b | 236.4x,a |
| UV-C | 5 | 201.2y,b | 230.5x,a | 189.2y,c | |||
| Control | 14 | 218.9x,b | 217.6y,b | 248.8x,a | |||
| UV-C | 14 | 213.3x,c | 237.4x,b | 251.1x,a | |||
| Flesh | Control | 5 | 85.8±3.9 | 95.7x,b | 76.5y,c | 105.9x,a | |
| UV-C | 5 | 87.6y,c | 100.0x,a | 97.5y,b | |||
| Control | 14 | 72.0y,b | 90.6y,a | 93.5y,a | |||
| UV-C | 14 | 75.1x,c | 103.9x,a | 100.5x,b | |||
| TFC (mg quercetin *100 gfw−1) | Peel | Control | 5 | 125.1±4.6 | 172.8x,a | 148.5y,b | 174.1x,a |
| UV-C | 5 | 133.2y,b | 174.3x,a | 137.0y,b | |||
| Control | 14 | 104.5x,b | 104.4y,b | 123.1y,a | |||
| UV-C | 14 | 101.8x,c | 110.3x,b | 131.7x,a | |||
| Flesh | Control | 5 | 15.6±1.0 | 22.3x,a | 18.7y,b | 21.5x,a | |
| UV-C | 5 | 17.4y,b | 23.2x,a | 17.7y,b | |||
| Control | 14 | 7.7y,b | 8.1y,b | 11.5y,a | |||
| UV-C | 14 | 10.1x,c | 17.4x,a | 14.8x,b | |||
| CAT specific activity (μmH2O2* min−1 •mg protein−1) | Peel | Control | 5 | 529.3±53.7 | 426.2y,b | 596.3x,a | 497.6x,b |
| UV-C | 5 | 688.0x,a | 102.1y,b | 113.7y,b | |||
| Control | 14 | 129.1x,b | 342.1y,a | 99.2y,c | |||
| UV-C | 14 | 75.2y,c | 462.5x,a | 156.6x,b | |||
| Flesh | Control | 5 | 439.9±45.0 | 671.0y,a | 375.3y,b | 634.3x,a | |
| UV-C | 5 | 895.0x,a | 600.6x,b | 521.2y,c | |||
| Control | 14 | 76.0y,b | 50.2y,b | 113.9x,a | |||
| UV-C | 14 | 80.2x,a | 67.4x,a | 69.3y,a | |||
| SOD specific activity (U•min−1•g protein−1) | Peel | Control | 5 | 8.8±0.5 | 7.3x,b | 7.0y,b | 7.9y,a |
| UV-C | 5 | 7.0y,c | 8.0x,b | 8.7x,a | |||
| Control | 14 | 7.9y,a | 8.2x,a | 7.6y,b | |||
| UV-C | 14 | 8.1x,a | 7.6y,a | 7.8x,a | |||
| Flesh | Control | 5 | 12.5±0.5 | 13.8x,c | 15.2x,b | 16.8x,a | |
| UV-C | 5 | 12.9x,c | 14.5y,a | 13.6y,b | |||
| Control | 14 | 10.6x,a | 7.3x,b | 7.0y,b | |||
| UV-C | 14 | 8.4y,a | 7.4x,b | 7.3x,b | |||
| POD specific activity (mM guaicol* min−1 •mg protein−1) | Peel | Control | 5 | 465.9±15.9 | 164.7y,b | 150.9y,b | 209.0x,a |
| UV-C | 5 | 198.2x,a | 178.2x,a | 168.8y,b | |||
| Control | 14 | 582.5x,b | 765.5x,a | 587.1x,b | |||
| UV-C | 14 | 443.6y,b | 546.8x,a | 440.6y,b | |||
| DPPH (radical inhibition %) | Peel | Control | 5 | 70.8±2.2 | 81.3x,a | 79.9y,a | 72.1x,b |
| UV-C | 5 | 76.7y,b | 81.8x,a | 66.7y,c | |||
| Control | 14 | 58.9y,a | 57.2y,b | 57.2y,b | |||
| UV-C | 14 | 60.3x,a | 57.7x,b | 59.8x,a | |||
| Flesh | Control | 5 | 33.6±1.2 | 29.9y,b | 34.1x,a | 31.4x,a | |
| UV-C | 5 | 33.2x,b | 35.0x,a | 27.4y,c | |||
| Control | 14 | 31.2x,c | 37.5y,a | 35.2y,b | |||
| UV-C | 14 | 27.0y,c | 39.8x,a | 37.5x,b | |||
| ABTS (radical inhibition %) | Peel | Control | 5 | 90.2±1.4 | 95.1x,c | 97.8x,b | 98.5x,a |
| UV-C | 5 | 94.5x,b | 98.0x,a | 98.3x,a | |||
| Control | 14 | 84.7x,a | 83.4y,a | 66.4y,b | |||
| UV-C | 14 | 84.7x,a | 85.0x,a | 79.9x,b | |||
| Flesh | Control | 5 | 59.2±1.9 | 57.0x,a | 56.1x,a | 51.9x,b | |
| UV-C | 5 | 56.5x,a | 57.4x,a | 45.1y,b | |||
| Control | 14 | 61.4x,b | 67.9y,a | 68.0y,a | |||
| UV-C | 14 | 51.4y,c | 84.1x,a | 73.7x,b | |||
Each observation is a mean±SD of n=6. UV-C, TPC, TFC, CAT, SOD, POD, DPPH, ABTS, GA and gfw indicate ultraviolet-C irradiation, total phenolic content, total flavonoid content, catalase, superoxidase, peroxidase, 2, 2-diphenyl-1picrylhydrazyl, 3-ethylbenzothiazoline-6-sulfonic acid, gallic acid and grams of fresh weight respectively. Statistical differences (P≤0.05) between Control and UV-C treatments are indicated by superscripts x and y, while for storage periods (5, 10 and 15 days) differences are indicated by superscripts a, b and c