Effect of passive evaporative cooling device on proximate composition and physicochemical properties of tomatoes (Lycopersicon esculentum)

To reduce postharvest loss of tomatoes' nutrients during storage, in a rural area where there is no electricity supply, an existing passive evaporative cooler (PEC) which consists of an overhead tank, a single faced pad system, storage chambers, tray, base plate, drain pipe, water distribution network and jute bag material was used. Thirty (30) fresh matured tomato fruits were obtained and divided into two groups. Their initial proximate composition and physicochemical properties were determined using standard methods before stored in the PEC of relative humidity and temperature of 99.0% and 26℃ respectively whereas others were stored on the shelf at room temperature (RT) of relative humidity and temperature of 75.0% and 29℃, respectively. At every 3 days interval, the samples were removed for analyses. Data were obtained in replicate and subjected to analysis of variance using Tukey Honest Significant Difference. Results showed that the shelf life of the tomatoes stored in PEC were prolonged without spoilage for about 18 days while those stored under RT lasted for less than 12 days before spoilage. Also, % moisture, ash, protein, fibre and soluble solid contents of tomatoes stored in the PEC slightly dropped within 18 days whereas those stored on the shelf at RT dropped drastically within 8-12 days. The PEC was found to retain the freshness of the tomatoes.