الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The colour of food has a great influence on their acceptability. A good jam should appeal to the eye as well as to the palate. For this reason, the colour of jam is a factor of considerable importance. The formation of dark coloured pigments in food during processing and storage is a very common phenomenon, this browning reaction is a major problem for the food industry because of the detrimental effects of the browning reaction. The major factor which must be borne in mind when considering colour change is the Maillard reaction with its resulting brown .pigments formation. Maillard reaction or non-enzymic browning is considered one of the major causes’ of quality loss during storage because its accompanied by undesirable changes in colour, flavour and a reduction in nutritive value. Therefore, the aim of this study was, to examine the effects of the container (glass vs. cans), time and.temperature of storage on the amount of browning pigments formed in jam. A total of 180 samples of commercially processed Marmalade and Apricot jam packed in tin plated cans with enamel coated lid and glass container were included in this study. The jam samples were stored at different temperatures (4°C, 25 °c and 40°C) for 21 weeks. These samples were subjected periodically to browning determination using spectrophotometer and HPLC, pH determination, sensory evaluation and Brix measurement. The results of present study revealed the following: 1. The storage temperature had a great effect on the acceleration of browning formation in both Marmalade and Apricot jam. 2. Also, the packing material had an effect on the browning formation in both types of jams. 3. Although, Apricot jam at zero time showed a lower colour intensity (absorbance of 0.12) than Marmalade jam (absorbance of 0.37). .4. Higher rate of browning formation was found in case of Apricot j am reaching up to 1809.1 increase in absorbance when stored as canned product at 40°C for 21 weeks. 5. Marmalade jam showed an increase in absorbance of only 412 for the products stored at 40 °c for 21 weeks in cans containers. 6. Upon storage the increase in absorbance of about 300 was found in Apricot jam after less than 3 weeks when stored at 40. DC in can containers and after 6 weeks in case of glass containers. 7. At 25 DC, 30.0. increase in absorbance was found after 9 weeks in cans and 12 weeks in glass containers. 8. At 4 DC, 30.0. increase in absorbance was found after 21 weeks of storage in cans.