الفهرس 
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Abstract
This investigation was carried out for two successive seasons 2009-2010 and 2010-2011, on ”Valancia” orange fruit. The fruits were harvested on the 2nd half of April each season (3rd week) from Elmaghraby orchard at Nobaria farm. The collected fruits were prepared by washing, waxing (paraffin wax with S.O.P.P as antifungal was used), sizing, inspection and finally packed in carton boxes of 8 kg each.
The boxes were stored in the refrigerator at two temperature 4ºC and 6ºC. Six boxes for each temperature; 3 boxes were kept for observation with no fruit withdrawal, and the other 3 were used for sampling for the physical, chemical and biochemical analysis.
Another 6 boxes were kept at ambient temperature 25±2ºC as control. the analysis were carried out at weekly intervals.
The physical analysis included; external appearance; loss in weight and microbial spoilage. The chemical analysis included; percentage of TSS; acidity, vitamin ’C’ and caroteniods.
The biochemical measurements concentrated in measuring the respiration rate of fruits as affected by both factors, low temperature and waxing.
It was found that as temperature of storage decreased the fruits was able to maintained its freshness as well as its chemical composition without change till 12 weeks (3 months), comparing to control fruits which could keep its marketability up to 2 weeks only.
At the end of storage period when the microbial spoilage exceeded 25%; loss in weight recoded 31.25% for control and only 7.5% and 5% for 4oC and 6oC storage temperature respectively.
No significant changes were noticed in SSC for both storage temperature 4oC and 6oC till the 6th week then it started to increase with the reduction in acidity content of the fruit juice on the 7th and 8th week for the two temperature respectively.It was recorded also that the respiration rate (mgCO2/h/kg) showed no change till the 8th week when the fungal infection started on the fruits, as well as waxing helped in its reduction where it acted as barrier with the external atmosphere for gas exchange and out of the fruit.
Regarding the fungal spoilage; the low temperature and waxing showed a significant effect; when it appeared on the 7th and 8th week for both storage temperature respectively.
from the obtained data, it was found that keeping the ”Valancia” orange at low temperature prolonged its storage period, but it should not go below 4oC otherwise fruits will suffer of chilling injury problems; which will reduce the marketability of the fruits.
The optimum storage temperature for ”Valancia” orange could be between 4oC and 6oC and that to have a marketable fruit after removal from cold, with good shelf life.