Design of the proper modified atmosphere packaging for fresh-cut broccoli raab (cv. Novantina).

Low oxygen controlled atmosphere was reported to be useful for fresh-cut broccoli raab cold storage in maintaining freshness and qualitative traits, whereas excessive accumulation of CO2 (10-15%) should be avoided. Starting from these finding the aim of this work was to individuate the proper modified atmosphere packaging (MAP) for fresh-cut broccoli raab in order to reach at the equilibrium the target atmosphere composition with low oxygen (3%) during cold storage. Broccoli raabs harvested from a commercial farm, were selected for defects and were cut from the stalks, obtaining the ready-to-use product. After washing the product was packaged in plastic trays sealed in bags of different plastic materials. Two commercially available polymeric coupled films (polypropylene/polyethylene terephthalate, PP/PET, and polypropylene/polyamide, PP/PA microperforated, MF), were used as packaging materials with or without the inclusion of a CO2 absorbers (used in 5-g sachets). For each packaging condition a passive (P-MAP) and an active atmosphere with 5% O2 in nitrogen (A-MAP) were used. Unpackaged samples were used as control and stored with all packages at 5 °C. Initially, and after 3 and 8 days samples were taken and quality attributes (overall appearance, odor, color analysis and weight loss) were evaluated. Gas concentrations (O2 and CO2) inside packages were also monitored. Among the packaging treatments tested the combination using PP/PA in A-MAP with the use of CO2 absorbing sachets reached equilibrium condition very close to optimal for broccoli raab. Fresh-cut broccoli raab stored in this condition for 8 days showed negligible reduction of appearance and odor scores, compared to the fresh samples resulting significantly higher than for the samples stored in all other packaging combinations.