EFFECT OF MICROBIAL ACTIVITY AND ENVIRONMENTAL FACTOR ON ASCORBIC ACID CONTENTS OF STORED TOMATO IN PASSIVE EVAPORATIVE COOLING STRUCTURES

A study was conducted to study the effect of microbial activity and environmental factor on ascorbic acid contents of stored tomatoes in Passive Evaporative Cooling Structures. Three sets of four different types of passive evaporative cooling structures made of two different materials, clay and aluminium were constructed. One set consists of four separate cooling chambers. Two cooling chambers were made with aluminium container (round and rectangular shapes) and the other two were made of clay container (round and rectangulars). These four containers were separately inserted inside a bigger clays pot and laterite walls inter- spaced with clay soil of 5 cm(to form tin-in-pot, pot-in-pot, tin-in-wall and wall-in wall) with the outside structure wrapped with jute sack. The other two sets followed the same pattern with interspacing of 7 cm and 10 cm respectively. The set with 7 cm interspace served as the control in which the interspace soil and the jute sack were constantly wetted at intervals of between. 2 to 4 hours depending on the rate of evaporation with water at room temperature. The other two sets (5 cm and 10 cm interspaced soil) were constantly wetted with salt solution (Table salt (Nacl)) at the same interval to keep the soil in moist condition. In addition, the control has no fans and the inner cooling chambers were not lined with polyethylene nylon while the other two sets have fans and their inner cooling chambers lined with polyethylene nylon. Freshly harvested tomatoes were used for the experiment and the temperatures were monitored daily while the ascorbic acid contents were determined at interval of three days for a period of sixteen days. The average temperatures and relative humidity recorded for the tinin-pot in the 5 cm. 7 cm and 10 cm soil interspace are 27.38oC/88.33%, 27.10 oC /90.47% and 27.09 oC /91.49% respectively. The average temperatures and relative humidity recorded for the pot-in-pot in the 5 cm. 7 cm and 10 cm soil interspace are 27.39 oC /89.60%, 27.07 oC /92.27% and 27.05 oC /92.53% respectively. The average temperatures and relative humidity recorded for tin-in-wall in the 5 cm. 7 cm and 10 cm soil interspace are 27.94 oC /86.84%, 27.04 oC /90.95% and 27.03 oC /91.0% respectively while the average temperatures and relative humidity recorded for wall-in-wall in the 5 cm. 7 cm and 10 cm soil interspace are 27.59 oC /87.25%, 27.09 oC /91.99% and 26.98 oC /91.72% respectively. The average fungal count and ascorbic acid contents are recorded for the tin-in-pot in the 5 cm. 7 cm and 10 cm soil interspace are 3.4 x 10 ppm /22.8mg/100ml, 3.38 x 10 ppm /23.2 mg/100ml and 3.48 x 10 ppm /23.1 mg/100ml respectively. The average fungal count and ascorbic acid contents are recorded for the pot-in-pot in the 5 cm. 7 cm and 10 cm soil interspace are 2.96 x 10 ppm/23 mg/100ml, 2.92 x 10 ppm /23.3 mg/100ml and 3.32 x 10 ppm /23.2 mg/100ml respectively. The average fungal count and ascorbic acid contents are recorded for the tin-in-wall in the 5 cm. 7 cm and 10 cm soil interspace are 3.2 x 10 ppm /23 mg/100ml, 3.36 x 10 ppm /23.1 mg/100ml and 3.36 x 10 ppm /23.3 mg/100ml respectively while the average fungal count and ascorbic acid contents are recorded for the wall-in-wall in the 5 cm. 7 cm and 10 cm soil interspace are 3.02 x 10 ppm /23 mg/100ml, 3.18 x 10 ppm /23.3 mg/100ml and 3.24 x 10 ppm /22.9 mg/100ml respectively.