Effects of CO2 Concentration on Postharvest Quality of ‘Jinyan’ Kiwifruit Under Controlled Atmosphere Storage: Evidence of Low CO2 Sensitivity

The ‘Jinyan’ kiwifruit is valued for its flavour and storability, but softens and decays rapidly after harvest. Controlled atmosphere (CA) storage offers an alternative to 1-methylcyclopropene (1-MCP), yet the CO2 tolerance of this cultivar was unknown. The fruit was stored at 1 ± 0.5 °C under 5% O2 with 1–4% CO2, plus 1-MCP and air controls. A key finding is that ‘Jinyan’ is sensitive to low CO2 in terms of firmness and SOD activity: 2% CO2 induced abnormal softening and reduced SOD activity within 40 days, indicating a critical safe range between 2% and 3% CO2. Targeting 3% CO2 risks injury under typical commercial fluctuations (±0.5%). To provide a safety margin, we recommend 5% O2 + 4% CO2. This regime delayed losses of firmness, acidity and vitamin C (Vc), and reduced decay (by 43.7% at 200 days). First-order kinetics confirmed a 39.2% reduction in softening rate. For commercial application, we recommend a maximum storage period of 160 days, during which 4% CO2 provides higher firmness (26.01 N), lower decay (6.67%) and better colour retention (h° = 106.44). Thus, 1 °C, 5% O2 + 4% CO2 is recommended as a safety buffer against low CO2 injury.