الفهرس 
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Abstract
Onion, Allium cepa, L., is considered as one of the most important crops in all countries. In Egypt, onion rank fourth after cotton, rice, and citrus. It is grown as a winter, summer and inter planted crop for mature dry bulbs and green onion with small amounts as a source of protein, mineral salts, and vitamins. The total weight losses of onions for this method reaches a maximum value of (50%), which are mostly due to moisture loss and deterioration by insects and microorganisms. Three different methods of onion storage have been tested and compared during this study. These methods included traditional storage, ventilated storage in vertical bins, and cold storage. The ventilated storage was studied under two different types of storage bins (metal and concrete). While the cold storage method was studied under three different types of storage sacks (burlap, polyethylene and strip plastic) and three different types of packing boxes (bamboo, wood and plastic). The following results were obtained for each storage method: Traditional storage method 1 The weekly ambient air temperature around the onion pile was ranged from 22.12(R@(BC to 33.27(R@(BC with an average value of 27.7(R@(BC and the corresponding air relative humidity was ranged from 78.7% to 52.60% with an average value of 65.65%. 2 The temperature distribution inside the onion pile was varied with different locations of measurement (eastcenter west) and different measuring times. 3 Onion moisture content was decreased in a higher rate during the first four weeks of storage (0.61% / week) and then starts to decrease in lower rate during the next eight weeks (0.18% / week), while it was remained nearly constant till the end of experiment. 4?There was no deterioration noticed during the first two weeks of storage. However by the end of storage period the accumulative loss due to deterioration of onion bulbs reached to 20.7% w/w. 5?Total weight loss of onion increased gradually up to the highest level of 4.21% w/w after 10 weeks of storage and starts to decrease up to a level of 1.23% w/w at the end of storage period. The record accumulative weight loss at the end of storage period was 29.88% w/w. Ventilation storage methods: 1 ?The recorded average temperature of air used for ventilation process was 27.61?C and 27.36?C for the metal and concrete masonry bins, respectively. The corresponding average air relative humidity was 62.86% and 61.31%, respectively. 2 ?For both types of storage bin, onion bulk temperature decreased at a higher rate during the first four weeks of storage and then starts to fluctuate based on the changes in the temperature of the ventilation air. The recorded average onion bulk temperature for the metal bin was (26.43?C) and the corresponding average onion bulk temperature for the concrete masonry bin was (24.8?C). 3?For all treatments stored in concrete and metal bins, the onion moisture contents decreased with the increase of storage time. The moisture content of onion decreased from an initial level of 87.59 % to a final levels of 81.49% and 77.9% for the ventilated metal and concrete masonry bins respectively. 4 ?Deterioration loss of onion stored in concrete masonry bin was lower than that stored in metal bin. By the end of storage period, the accumulative deterioration loss of concrete masonry and metal ventilated bins was 7.81%w/w and 10.45%w/w, respectively. 5 ?The accumulative weight loss of the ventilated concrete masonry and metal bins was 16.91%w/w and 22.89%w/w, respectively at the end of storage period. 6 ?For both type of ventilated storage bins no sprouted bulbs were observed before the end of storage period. Cold storage method: 1 Average air temperature of cold room was (3.52) (R@(BC. The corresponding relative humidity of air was (77.88)% 2?The onion average bulk temperature was relatively decreased in a higher rate during the first four weeks of storage and it was relatively lower as compared with air temperature inside the storage room. The recorded average onion bulk temperature for polyethylene, burlap and strip plastic sacks with, (3.62), (3.88) and (3.46)(R@(BC respectively. The corresponding, value for bamboo, wood and plastic boxes was (3.42), (3.74) and (3.63)(R@(BC, respectively. 3?The reduction rate of moisture content was varied with the type of storage sacks and boxes. The final moisture contents for the onion stored in, polyethylene, burlap and strip plastic sacks were 86.48, 86.41 and 85.76%, respectively. The corresponding final moisture contents for bamboo, wood and plastic boxes were 86.07%, 85.91% and 86.07%, respectively. 4 Onion deterioration loss was varied with the type of storage containers. The recorded final accumulative deterioration loss of stored onions was 1.82 ,2.35 and 2.11%w/w for polyethylene, burlap, and strip plastic sakes respectively and the corresponding values for bamboo, wood and plastic boxes was 2.79, 2.31 and 1.99% w/w respectively. 6 The recorded final sprouting percentage of onion stored in polyethylene, burlap and strip plastic sacks were 4.5, 7.1 and 5.4%w/w respectively. While, the corresponding sprouting percentages for bamboo, wood and plastic boxes were 7.2, 6.4 and 5.6%w/w respectively