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

Polyunsaturated fatty acid (PUFA) degradation by lipoxygenase (LOX) may 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 storage resulted in increased chlorophyll and C-18 polyunsaturated fatty acids (PUFA) in broccoli florets by 96 hr. Reduced chlorophyll, PUFA and soluble protein were observed in nonpackaged (NP) samples. Chlorophyll remained near initial levels in vent packaged (VP) products. AM resulted in increased relative PUFA and reduced losses of soluble protein. 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 followed a trend similar to PUFA changes in both samples. No differences were found among treatments when enzyme activity was expressed on soluble protein basis.