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.
