High CO2 short-term treatment to preserve the quality of artichoke heads during cold storage

The effect of short-term treatment with high CO2 atmospheres on the postharvest quality of artichoke (Cynara cardunculus L. subsp. scolymus Hayek, ‘Violetto’) was studied. After harvest, artichoke heads were closed for 48 h at 0 (±1) °C in the modified atmosphere with three CO2 concentrations (CO2-10%, CO2-20% and CO2-30%) in 10% O2 and nitrogen or left in air (AIR) as control. Then, bags were opened and all samples (CO2-10%, CO2-20%, CO2-30% and AIR) were stored for 6 days at 5°C in air. At harvest and just after CO2 short-term treatment, chemical parameters were analyzed, including total phenol content (TP), antioxidant activity (AA) and ammonium content (AM), while respiration rate (RR) and texture (TX) were evaluated also during the storage in air at 5°C. One day after CO2 short-term treatment, AA and TP resulted significantly higher in CO2-10% and CO2-20%, while the lowest values were detected in CO2-30%, as a consequence of polyphenols oxidation. As for AM, artichoke heads treated with CO2-30% reported the highest ammonium content (about 11.3 µmol NH4+ g-1), followed by AIR samples, while the lowest values were measured in samples treated with CO2-10% and CO2-20% (mean value 3.2 µmol NH4+ g-1). During storage time, TX did not change significantly, while a significant reduction of RR compared to fresh artichokes (100.3±8.3 mL CO2 kg-1 h-1) was shown in all treatments. In particular, after 1 and 5 days post-treatment, artichoke heads treated with CO2-10% showed the significantly lowest RR, followed by samples treated with CO2-20%. Comparing treatments, artichoke heads stored in CO2-30% had the highest RR. These data showed that treatment with high CO2 concentration (30%) applied for 48 h at 0 (±1) °C might cause damage in artichoke heads during storage, while lower CO2 concentrations (10 and 20%) could be recommended.