ORANGE FLAVOR ABSORPTION INTO VARIOUS POLYMERIC PACKAGING MATERIALS

Citrus oil components (from cold-pressed and terpeneless oils), which contribute substantially to flavor of orange juice, were shown to be absorbed into various polymeric materials [low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), and surlyn (S)] used in aseptic packaging. Equilibration of absorption took place within 4 days, while extraction of the oil constituents occurred in 24 hr when higher temperatures were used. Substantial absorption of oil constituents by LDPE and S occurred while highly crystalline polymers (PP and HDPE) did not absorb much. The degree of absorption also depended on the nature of the oil constituents. Absorption was higher for terpene constituents followed by sesquiterpenes and aldehydes. Swelling factors showed that highly crystalline polymers (HDPE and PP) swelled less than crystalline polymeric materials. Citrus oil affected the crystallinity of the polymers by lowering their melting point and percent crystallinity.