Influence of modified atmosphere packaging on shelf-life of whole and sliced 'Cardoncello' mushroom (pleurotus eryngii)

The aim of this study was to optimize modified atmosphere packaging (MAP) for whole and sliced ‘Cardoncello’ mushrooms, a typical mushroom of south Italy. Whole mushrooms were packed in active MAP (initial gas concentrations 5 kPa O2 + 10 kPa CO2 in nitrogen) using polypropylene (PP) or polylactic acid (PLA) films, with or without microperforation (MP), and stored for 27 days at 0°C. Sliced mushrooms were packed in the same atmosphere in PP films with two levels of microperforations (MP1 and MP2) and stored for 14 days at 0°C. For both experiments, an air-control treatment (CTRL) was also considered. Mushroom respiration rate, headspace gas composition, weight loss, firmness, colour, pH, total soluble solids, acidity, total phenols, antioxidant activity, microbial and sensory quality were measured. For whole mushrooms, results indicated that the storage in microperforated packages better preserved the aroma compared with CTRL whereas samples stored in non-perforated films showed quick development of hypoxic conditions. Samples stored in PP-MP showed a lower oxygen reduction and a higher CO2 accumulation compared with PLA. Moreover, samples stored in PLA showed a higher weight loss compared with PP. Samples stored in PP-MP showed a lower growth of mesophilic bacteria, yeast and moulds compared with samples stored in PLA-MP. For sliced mushrooms, there were no differences in gas composition between PP-MP1 and PP-MP2 films. Cutting significantly affected aroma; mushrooms stored in PP-MP1 maintained the aroma better than samples in PP-MP2 or samples in CTRL. Storage in MAP delayed the growth of mesophilic bacteria as well as yeast and moulds compared with CTRL, with PP-MF1 being more effective than PP-MP2. In conclusion, the use of MAP delayed quality loss, extending the shelf-life of whole and sliced mushrooms at 0°C. In addition, best results were obtained with microperforated polypropylene, for both whole and sliced ‘Cardoncello’ mushroom