Valuation of postharvest loss and identification of its causes enables to develop proper measures required to reduce losses. The study was conducted at “Fogera” District, South Gondar, Ethiopia between 2017 and 2018 years to assess the extent of postharvest loss of tomato (Solanum lycopersicum L.) and to identify major causes with respective handling system. In this study, a total of 125 farmers and 40 traders (10 wholesalers and 30 retailers) were involved as main respondents. Data collection was done using semi structured interview schedule, key informant interview, focus group discussion and observation. Besides respondents estimation, a sample analysis was conducted to estimate the extent of postharvest loss as per the FAO minimum quality standards. Descriptive statistics such as average, percentage, frequency and standard deviation were used to analyse data and tables, graphs and charts were used to present result. Result revealed that almost half of tomato produced is damaged and puts out of normal use with highest loss at producer level due to different causes which are complex and interrelated across tomato market chain. Marketing situation, insect pest and disease, lack of awareness, low economic status of producers, late harvesting, mechanical damage during harvesting and transportation, poor quality of produce and price fall were some of the reasons identified as major cause of post-harvest loss of tomato. For solving the postharvest loss problems, actors in supply chain has to develop cooperation and effective communication among all the research, extension, and industry personnel involved.

The purpose of this research was to determine the optimum dehydration temperature and time length for a better physicochemical quality of tomato powders. The treatments consisted of 70, 80 and 90°C dehydration temperatures and 9, 11, and 13 h time durations arranged in a completely randomized design (CRD) with triplicates. The inlet and outlet air temperatures of the hot air oven dryer were about 24 and 60°C respectively with an air velocity of about 2.9 m/s. Fresh tomatoes were used as a control. It has been observed that the major quality parameters of tomato powders were significantly increased with increasing dehydration temperature and time up to 80°C and 11 h respectively. When the dehydration temperature and time length went beyond 80°C and 11 h respectively, the quality of tomato powders declined. The maximum TSS content (7.433 °Brix), titratable acidity (0.4967), rehydration ratio (3.437), lycopene content (0.4512 mg/100 g) and lower pH value (4.433) were obtained at 80°C temperature and 11 h dehydration time. Moisture content was reduced to 11% at the same dehydration temperature and time length without considerable physiochemical quality loss. Inversely, vitamin C was reduced as dehydration temperature and time increased. Generally, the results of this study showed that dehydration of tomatoes with 80°C and 11 h temperature and time length respectively, provides better physicochemical quality of tomato powders. Future research is suggested on consumers' acceptance of dehydrated tomato powders.