Effects of packaging material and storage conditions on vitamin C concn. and colour of orange juice were studied. Concentrate orange juices were packaged in glass, monolayer PET or multilayer PET (PET/nylon + oxygen scavenger/PET) with Al foil closures and stored at 20(deg)C for 9 months in the dark or under artificial light. Glass provided best vitamin C retention; vitamin loss was associated with O SUB 2 permeability in PET samples. Lighting conditions did not significantly influence vitamin C concn. during storage. Analysis of colour changes in orange juice stored under artificial light revealed decreases in L (lightness) and b* (yellowness ) values accompanied by increases in a* due to brown pigment formation. Colour changes could be partly correlated with packaging O SUB 2 permeability. Additional studies on aroma compound permeation from PET bottles with HDPE closures indicated that most aroma was lost through closures; losses could be minimized by use of a multilayer HDPE-based closure incorporating an internal barrier of LDPE/EvOH/LDPE.
