Evaluation of quality and shelf life of fresh tomatoes stored in a pumice padded evaporative cooler with a roof pond

Abstract

The world is faced by myriad challenges like climate change and ever-increasing population making the achievement of global food security a challenge. Although highly perishable, tomatoes are popular food commodity. Farmers have to sell the commodity soon after harvest for fear of deterioration. For longer storage, tomatoes require an environment with low temperature and high relative humidity. Cooling systems such as refrigeration are not accessible to most small-scale farmers because they require connection to the grid. In this study, a solar powered pumice evaporative cooler was developed and evaluated for the storage of ripe tomatoes. The system adopted the principle of evaporative cooling and comprised of walls filled with pumice coupled with a pond filled with water on the roof and below the storage space. This design allowed water to drip from an elevated tank through the pumice walls and drain into the reservoir below the storage space before recirculation using a solar powered pump. Mature tomatoes c.v Ann F1 were harvested at the turning stage and stored both in the cooler (treatment) and under ambient conditions (control). Quality attributes namely pH, total soluble solids (TSS), firmness, colour and shelf life were evaluated on a seven-day interval for 28 days. Results showed a significant (p≤0.05) difference for pH, TSS, and firmness between samples stored in the cooler and control. However, there was no significant (p>0.05) difference in the colour (hue angle) for the fruits under the treatment and control. Compared to the control, the developed solar powered storage system increased the shelf life of tomatoes from 14 days to 28 days. The results from this study indicate that the solar powered pumice evaporative cooler preserves the quality of tomatoes. This enables the farmers to get better returns as they do not have to sell their harvest at low prices for fear of deterioration.