Controlled atmosphere storage of celery with the silicone membrane system

Laboratory experiments were performed to assess the potential of the silicone membrane system for long term storage of celery under controlled atmosphere (CA) conditions. Designed CO₂ levels of 1.5, 3.5 and 5.5% were selected to calculate the silicone membrane areas to be installed on the chambers. Visual observations, mass losses and physiological analyses were the means selected to assess the quality of the product. Pascal celery, imported from California (USA), was stored at 1.5°C for 29 days under regular atmosphere (RA) with 80% relative humidity (RH), and 128 days under averaged carbon dioxide (CO₂)+oxygen(O₂) concentrations of 0.8+17.7, 2.0+12.6 and 4.0%+9.2% with RH close to saturation. The results showed that the first two CO₂+O₂ combinations were the most suitable CA compositions, among those tested, for long term storage of that cultivar, with total mass losses of less than 30 and 23% respectively. Clean cut celery, grown locally in Québec on organic soil, was stored at 1.5°C under RA with 80% RH and under three CA compositions (1.1+ 14.8, 2.3+7.9 and 3.2% CO₂+5.5% O₂) with RH close to saturation for 62 and 71 days, respectively. The total mass loss averaged 25% and no significant difference was observed between the RA and CA stored celery. In the experiment with Clean cut celery, the losses were mainly attributed to bacterial infections. Both celery cultivars stored under CA with high RH showed better texture and crispness than those stored under RA. It was also noted that the total sugar content significantly increased with storage.