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Optimized air flow in commercial CA storage room for apples

Neuwald, D. A., Kittemann, D., Spuhler, M., Rux, G., Linke, M., Geyer, M.
Acta horticulturae 2015 no.1079 pp. 403-407
air, air flow, air temperature, apples, color, controlled atmosphere storage, evaporation, firmness, fruit quality, logging, relative humidity, titratable acidity, total soluble solids, transpiration, weight loss
During a second experimental year we investigated the impact of storage room modifications on an optimized air flow. As in the first year the parameters investigated were temperature, humidity, air velocity, weight loss and fruit quality distribution. Therefore, two commercial CA rooms (40 tons each), one without (‘not-optimized’) and the other one with (‘optimized’) air deflector and evaporator sealing-off, were equipped with fruit temperature sensors at different fixed positions in the room. At the same positions, air velocity was measured with a hand held anemometer. In addition, relative humidity and air temperature were logged. Weight loss and fruit quality (firmness, titratable acidity, total soluble solids and skin colour) of the apples were determined for each measuring point after storage. Additionally to the first year we determined the transpiration rate of the fruit. An interpretation of air velocity measurements was not possible in the second year, due to technical problems during measurement. The average values for fruit temperature were lower in the ‘optimized’ room for all measuring points. Concerning fruit quality no differences have been observed between both rooms. As in the first year relative humidity was about 4% higher in the ‘optimized’ room. On the other hand higher transpiration rates were measured in this room, possibly caused by an increased evaporation due to ‘optimized’ show higher air flow near fruit surface. In contrast to these findings and to results from first year, weight loss was slightly lower in fruit from the ‘optimized’ room. The experiment of the second year partly confirms results obtained during the first year. Further experiments will be necessary to validate results obtained so far. For that matter it is important to include the determination of air turbulences in the rooms to support the interpretation of air velocity measurements.