الفهرس 
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Abstract
A study was carried out to test and evaluate the effect of three different drying methods of sunflower seeds (forced convection solar drying, accelerated drying and the traditional sun drying) on physical quality and chemical constitutes of the dried seeds. The safe storage period of the dried seeds stored in vertical storage silos was determined and evaluated in terms of oil content, peroxide number and free fatty acids.
Methods and Result: The experimental treatments of the solar drying method included three different absorber plates (perforated aluminum, perforated iron and perforated plastic sheets) and three different air velocity (0.5, 1 and 1.5 m/sec). While the accelerated drying experimental treatments included eight different cylinder surface temperatures (75, 85, 95, 105, 115, 125, 135 and 145oC and five different exposure times (3, 6, 9, 12 and 15 min.). According to the results of the drying experiments, the best treatments of the tested drying methods were used for storage experiments. The experimental measurements included surface temperature of the rotary cylinder, bulk temperature of the heat-treated seeds, ambient air temperature and relative humidity, temperature and relative humidity inside the solar dryers, seeds bulk temperature inside the storage silos, the quality changes of sunflower seeds, and the overall thermal efficiency of the solar dryer. The results show that, for the accelerated drying process, heating surface temperature of 145oC and the exposure times of 15 min was found to decrease the moisture content of seeds to the safe storage level of 5.8% w.b with a fungal load of 102 colonies/g and free fate acid of 1.97%. The green-house type solar dryer with aluminum absorber plate operated at 1.5 m/sec air velocity decreased the moisture content to a level of 7.8 % w.b with a fungal load of 1122 colonies/g and a percentage of free fatty acids (2.04%). For the storage experiments, the fungal load count of the silo filled with naturally dried seed was drastically increased up to 41.41% after 12 weeks of storage. However, the fungal load count of the solar dried seeds and the accelerated dried seeds increased only by 36.54% and 8.05%, respectively. Meanwhile, the accelerated drying method recorded the lowest percentage of free fatty acids (F.F.A) at the end of storage period (2.39%) followed by the solar and the naturally dried seeds.