Abstract
Changes in antioxidants, rehydration ratio and browning index of tomato slices (raw and blanched) coated with gum arabic of different concentrations (1, 5 and 10%) and dried by sun (40 +/- 1C) or air (80C) were monitored during storage (6 months) at 24 +/- 1C. Sun- and air-drying of raw and blanched slices significantly (P0.05) increased the total phenolics, flavonoids and lycopene contents but significantly (P0.05) decreased ascorbic acid. Storage of dried coated raw and blanched slices increased total phenolics compared to uncoated. Flavonoids, ascorbic acid, lycopene and rehydration ratio were significantly (P0.05) decreased. However, coating of raw and blanched slices reduced the level of losses in antioxidants, color and rehydration ratio during drying and storage. As the concentration of gum arabic increased, the rate of reduction in antioxidants, color and rehydration ratio decreased, and there was a remarkable increase in some antioxidants during storage. Practical Applications Limited shelf life and loss in quality are major problems in marketing of fresh tomatoes. An ideal preservation method should increase the shelf life of tomatoes without causing notable loss of quality. Dehydration of tomato slices had a great impact on the constituents of the slices, but application of surface edible coating prior to dehydration reduced losses in fruit composition and kept the quality attributes of the final product.