SOFTENING OF KIWIFRUIT IN STORAGE. EFFECTS OF INTERMITTENT HIGH CO₂ TREATMENTS

The storage performance of kiwifruit (Actinidia chinensis Planch., var. Hayward) was evaluated during long term storage at O°C. The effects of intermittent 10% CO₂ (one week at 10% CO₂ followed by one week in air) or intermittent 30% CO₂ (3.5 days at 30% CO₂ followed by 3.5 days in air) exposures at 0°C were studied. Two, four and six intermittent exposures were compared with normal conditions of storage in air with special emphasis on the first 11 week period of storage where deformation characteristics of fruit were followed by non destructive testing. In all cases, we observed a significant effect in delaying the softening of kiwifruit at 0°C ; this effect increased with the number of exposures to CO₂. However, when fruit were subsequently transferred into air, the rates of softening were comparable to those of fruit stored continuously in air at 0°C. Nevertheless, after 32 weeks of storage, a remanent effect was still detectable in the six 30% CO₂ exposures treatment, in which the fruit were significantly firmer than in the other treatments.