Effect of preharvest UV-C treatment of tomatoes (Solanum lycopersicon Mill.) on ripening and pathogen resistance
Matthew A. Obande, Gregory A. Tucker and Gilbert Shama
Postharvest Biology and Technology, Volume 62, Issue 2, November 2011, Pages 188-192
2011
บทคัดย่อ
Treatment with UV-C of tomato fruit on the vine was conducted using a mobile unit that was designed to be conveyed between the rows of tomato plants in a commercial glasshouse. Trusses of fruit both at the ripe and mature green phase were treated with UV-C doses of 3 and 8 kJ/m2. Ripe fruit were picked 8 h after treatment and kept at room temperature for up to 16 d during which colour development and texture were monitored and compared to untreated controls. Mature green fruit treated on the vine with UV-C doses of 3 or 8 kJ/m2 showed only a slight loss in green pigmentation in contrast to the tomato colour index (TCI) of control fruit which increased sharply 5 d after treatment. The TCI of ripe fruit treated with UV-C at a dose of 8 kJ/m2 showed a lag of 10 d before increasing to a final value comparable to that of untreated fruit. Fruit treated with a dose of 3 kJ/m2 did not display a lag but the increase in TCI occurred at a lower rate than for the controls. Firmness remained higher in fruit treated with the highest UV-C dose compared to fruit treated with the lower UV-C dose and controls. Fruit covered with UV impermeable film on the same plants as those that had received a UV-C dose of 3 kJ/m2 had become ripe by day 6 in a manner similar to that of the controls. By contrast, fruit from trusses adjacent to those that had been treated with a UV-C dose of 8 kJ/m2 remained green over the same period of time. Ripe fruit treated as described above were inoculated with spores of Penicillium digitatum after UV-C treatment and their firmness monitored over 12 d. A dose response effect was found with fruit treated at the highest dose remaining firmer than those treated at the lower dose and the controls.