THE EFFECT OF IRRADIATION ON SWEET CHERRIES

The effect of irradiation (1, 2.5 and 5 kGy) and packaging (Resinite V F71) on the shell life of cherries (Prunus avium cv. Germersdorfi oria s) was studied. Cherries were stored for 7-26 d (3-5 degrees C, 90% RH ). The spoilage, weight loss, texture, sugars and organoleptical prope rties (color, taste, texture, surface) were determined. The ultrastruc ture of cells (SEM, TEM, image analysis) and cell wall of the packed a nd stored (7 d) cherries were investigated. Irradiation (2.5 kGy and 5 Gy) reduced spoilage after 7 wk of storage at 3-5 degrees C from 60% to 20%. Packaging inhibited spoilage, by 20% (from 50% to 30%), and we ight losses nearly completely (from 3-5% to 0.2-0.3%)1 Combined treatm ent (2.5 kGy and packaging) resulted in the best results: spoilage was in average 10%. Irradiation (2.5 kGy) induced softening (P > 95%). Du ring storage time softening increased (P > 95%) both in the control an d in the irradiated cherries. However, panelists could not establish s ignificant differences between texture of control and irradiated cherr ies. The ultrastructure of cells in the cherries showed great heteroge neity (cell size, thickness of cell wall, integrity of cell compounds) . Cells of the cortex in irradiated cherries were more wrinkled (SEM) than in the control. The middle lamellae of cell wall dissolved modera tely in the irradiated (1, 2.5 key) cherries (TEM). Glucose and fructo se were detected in cherry. The quantity of these sugars did not chang e with the increasing radiation dose. During storage fructose concentr ation increased, glucose concentration decreased. On the basis of thes e results irradiation (2.5 kGy) can be applied for extension of the sh ell life of cherry. Three times longer storage time (at 3-5 degrees C, 90% RK) can be obtained by irradiation, even longer by using irradiati on combined with packaging.