PACKAGING INFLUENCED TOTAL CHLOROPHYLL, SOLUBLE-PROTEIN, FATTY-ACID COMPOSITION AND LIPOXYGENASE ACTIVITY IN BROCCOLI FLORETS

Polyunsaturated fatty acid (PUFA) degradation by lipoxygenase (LOX) ma y contribute to postharvest deterioration of vegetables and fruits. In broccoli, modified atmosphere packaging (MAP), automatic misting (AM) and vent packaging (VP) may reduce postharvest deterioration. MAP sto rage resulted in increased chlorophyll and C-18 polyunsaturated fatty acids (PUFA) in broccoli florets by 96 hr. Reduced chlorophyll, PUFA a nd soluble protein were observed in nonpackaged (NP) samples. Chloroph yll remained near initial levels in vent packaged (VP) products. AM re sulted in increased relative PUFA and reduced losses of soluble protei n. VP reduced PUFA and soluble protein. Optimal pH of broccoli floret LOX was 5.5-6.0. Water-soluble LOX activity in MAP and NP samples foll owed a trend similar to PUFA changes in both samples. No differences w ere found among treatments when enzyme activity was expressed on solub le protein basis.