Modified-atmosphere storage of kiwifruit (Actinidia chinensis Planch) with ethylene removal

Abstract ‘Bruno’ kiwifruits were stored at −1°C in sealed polyethylene bags of varying thicknesses, with and without a C2H4 absorbant (Ethysorb). The gaseous composition of the modified atmospheres generated by the respiration of the fruit was dictated by the thickness of the polyethylene and the presence of the C2H4 absorbant. The ripening rate of the fruit and its keeping quality during 6 months of storage and 7 days subsequent shelf-life at 20°C were compared with those of fruit stored in unsealed 0.02-mm polyethylene bags. Without C2H4 removal from the storage atmosphere, there was no significant effect of the modified atmospheres in the sealed bags on the rate of fruit ripening and no improvement in its keeping quality. However, when C2H4 was absorbed from the storage atmosphere, post-storage fruit ripening was retarded by increasing the thickness of the polyethylene bag and, as a result, the CO2 level within it. This was indicated by a significantly negative correlation between the CO2 level in the bags and the increase in SSC and a significantly positive correlation with fruit firmness. The retarded fruit softening resulted in an improved keeping quality, and the storage life of ‘Bruno’ kiwifruits could therefore be extended to 6 months by storing the fruit at −1°C in sealed 0.04–0.05-mm-thick polyethylene bags containing a C2H4 absorbant. The average composition of the atmosphere in these bags was 3–4% CO2, 15–16% O2 and