Short hypobaric treatments potentiate the effect of chitosan in reducing storage decay of sweet cherries

The effectiveness of chitosan and short hypobaric treatments, alone or in combination, to control storage decay of sweet cherries, was investigated over 2 years. In single treatments, chitosan was applied by postharvest dipping or preharvest spraying at 0.1, 0.5, and 1.0% concentrations; hypobaric treatments at 0.50 and 0.25 atm were applied for 4 h. In combined treatments, sweet cherries were dipped in 1.0% chitosan and then exposed to 0.50 and 0.25 atm, or sprayed with chitosan (0.1, 0.5, and 1.0%) 7 days before harvest and exposed to 0.50 atm. soon after harvest. Untreated sweet cherries kept at normal pressure (near 1.00 atm) were used as controls. Rot incidence was evaluated after 14 days storage at 0 +/- 1 degreesC, followed by a 7 day shelf life. In both years, chitosan and hypobaric treatments applied alone significantly reduced brown rot, grey mould, and total rots, the latter also including blue mould, Alternaria, Rhizopus and green rots. A combined treatment with 1.0% chitosan and 0.50 atm was the best in controlling decay, showing in the first year, a synergistic effect in the reduction of brown rot and total rots. The results indicate that the combination of hypobaric and chitosan treatments is a valid strategy for increasing the effectiveness of the treatments in controlling postharvest decay of sweet cherries. (C) 2002 Elsevier Science B.V. All rights reserved.