The storage effects of calcium-fortified orange juice concentrate in different packaging materials.

Orange juice concentrate has been fortified with calcium in order to fulfil part of the recommended daily allowance of calcium and to overcome the problem of the shortage of milk and dairy products in Egypt. The loss of quality of calcium-fortified and unfortified orange juice concentrate was evaluated in three different packaging materials and when stored for ten weeks at room temperature. The results showed that vitamin C content decreased during storage for both the fortified and the unfortified samples. The trend of ascorbic acid breakdown was similar in all packaging treatments. The total titratable acidity declined during storage period; however, the decline was higher in the unfortified sample than in the fortified one. Also, the pH values increased along with the storage period. The results illustrated that the color values of both the fortified and unfortified diluted orange juice concentrate changed little at the end of the storage period. However, the samples packaged in low density polyethylene bags had the higher orange in the color values R and Y. The changes in the iron content for both samples was negligible during the storage period. However, a very slight change in the calcium content (4.5% and 4%) was observed after ten weeks of storage for both the unfortified and the fortified samples respectively. The acceptability of fortified orange juice rated higher than the unfortified one. The panelists' evaluation values were affected by the packaging treatment and storage time. The samples packaged in low density polyethylene bags had a higher level of decline of the panelists' evaluations than the ones packaged in laminated pouches or cans, while the latter had a lower level of decline.