PHD theses : Engineering

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    EFFECT OF STORAGE CONDITIONS
    (Al Neelain University, 2011) MOHAMED MOHAMED AHMED ELAWAD
    The idea of this research came during June 2006 when an announcement was given by the British Broadcasting Corporation (BBC) about the withdrawal of four soft drinks brands, because of the discovery of some hazardous chemicals found in these drinks due to bad storage conditions. In Sudan such problem is expected even to be worse, because of the sever storage conditions of these products. Because of the importance of such problem to public health were decided to investigate it. Three types of samples were selected two brand of soft drinks ( lemon and apple flavored ) and a mineral water . Six samples were packed in plastic container (polyethylene terephthalate - PET ). Two samples packed in glass bottles. The samples had been taken from a shopping center at the center of Khartoum city. Part of the samples were stored in a refrigerator and the corresponding copies from the same patch were stored in the open air as they stored in shopping centers. Between 6 – 8 months these samples were analyzed in a specialized laboratories with Gas chromatography-mass spectrometer ( GC-MS ). The results of the research showed the following - polyethylene terephthalate oligomers as well as acetaldehyde residues were not found, which proved that the polymer is stable and clean. - Most of polymer additives, which were migrated from PET in all open air samples were found with higher concentrations ensure that the storage condition affects the products. - Existence of additional compounds in sample S2G ( lemon flavored ) probably released from stopper lining plastic. - The explained of absence of such additional compounds in sample S3G ( apple flavored) means the absence of stopper lining plastic in the glass sample . The recommendations are :- - It was adviced to stick to PET usage as beverage container, because it proved to be more safe for this purpose. - To avoid usage of any other polymer material for stoppers or covers. - Storage of beverages should be in standard condition, like other food products . - It was recommend to go back to glass. - Further investigations in the same field with different liquids ( e.g. edible oil ) to check the effect of other storage condition ( e.g. freezing )