Optimizing modified atmosphere packaging for freshcut broccoli raab (Brassica rapa L.)

Broccoli raab, is a typical Italian vegetable, extensively cultivated in Southern Italy. The edible portion is represented by the central inflorescence and has a very appreciated light-bitter taste. A greater increase in consumption could come from a ready-to-use product, however they are very perishable, and technologies aimed to prolong product shelf-life are necessary. In this work active and passive modified atmosphere packaging (MAP) were investigated in order to achieve and maintain the optimal atmosphere composition during cold storage: 1) polypropylene/polyamide microperforated bags (PPPA MF) (22x32 cm), with initial gas composition of 2% O-2/98% N-2; 2) polypropylene bags (PP) (22x32 cm), with initial gas composition of 4% O-2/96% N-2; 3) passive MA in shrink-wrap packaging (pMAP); 4) air (CTRL) within macro perforated bags. Fresh cut broccoli raab consisting of compact florets with stems similar to 10-cm long, including tender leaves, were stored as described up to 12 days at 5 +/- 1 degrees C. PPPA MF and PP accumulated after 12 days of storage approximately 10% of CO2, reaching instead different O-2 percentage: 1 and 10% for PP and PPPA MF, respectively. The final atmosphere composition led to a difference in the sensorial evaluations, with PP showing the higher off odor score and PPPA MF intermediate value if compared to control sample. PPPA MF stored broccoli raab obtained the best visual quality score and no significant differences were found between treatments regarding chemical and physical parameters (DHA, vitamin C, TPC, AC and firmness). The three tested materials allowed to reduce weight losses compared to air storage. PPPA MF showed the best performance in maintaining quality losses during storage of fresh cut broccoli raab, but a shelf life shorter than 12 days should be considered in order to minimize off odor development.