Effect of gamma radiation on tomato (Lycopersicon esculentum) quality during storage and processing

Two tomato cultivars grown in Sudan, seasons 2010/ 2011, namely Amani and Bet086 were exposed to gamma rays doses of 0.25, 0.50 and 1.00KGy to delay their ripening and hence extend their shelf life. Irradiated tomato fruits were packed in carton boxes, stored at 15±1 deg C (85- 90% R.H) and eventually examined for changes in physical, physico-chemical and organoleptic qualities during storage as well as their processing properties. Bet086 tomato cultivar recorded minimum weight loss (11.97%) compared to Amani cultivar (12.31 %) treated with 1.00KGy. Gamma rays treatment helped reduce respiration rate of Amani tomato cultivar (36.79, 35.39, and 34.36 mgco2/ Kg/ hour for the three doses, respectively) compared to the control tomato fruits (44.34 mgco2/Kg/ hour). The loss in flesh firmness in the control tomato fruits was significantly (p 0.05) faster (0.07 Kg/c square m) after 12 days of storage compared to Amani tomato fruits treated with the three doses of Gamma rays (0.06, 0.06, and 0.05 Kg/c square m, respectively) in 24 days of storage. At the end of the storage period, Bet086 tomato recorded best firmness (0.06Kg/c square m) after treatment with 1.00KGy compared to Amani tomato fruits (0.05 Kg/c square m). Optimum acidity was recorded by Bet086 tomato fruit treated with 1.00KGy and stored for 24days (0.4% citric acid). After 21 days of storage, irradiation was found to improve the level of total soluble solids in tomato fruit particularly in Beto86 fruits. Gamma rays was found more effective in delaying color development, and in retention of ascorbic acid in tomato fruits (22.49mg/100g) in control spoiled in 12 days and in fruits treated with gamma rays stored for 24 days. Slices prepared days were found more acceptable in color, taste, texture, and flavor compared to the control fruits. Also paste prepared from Beto86 fruits treated with three doses of gamma rays was found to be better in color, consistency, taste, and flavor compared to paste made from the control fruits