UC Davis

Modified atmospheres (MA) have been shown to delay senescence of some leafy greens. This study explored the effect of modified atmospheres with elevated CO2 on baby kale and arugula shelf life and sensory quality. The ready to eat baby kale was stored at 5 °C in six different atmospheres: 1) 5% O2 + 5% CO2, 2) 5% O2 + 10% CO2, 3) 5% O2 +15% CO2, 4) 10% O2 + 10% CO2, 5) 10% O2 + 15% CO2 and 6) 20% O2 + 0.03% CO2 (Air), or in Air at 0 °C. Chlorophyll degradation was significantly retarded in every MA treatment compared to the kale stored in Air at 5 °C, which led to a significantly better visual quality scores. However, when high CO2 (15%) was combined with low O2 (5%) storage at 5 °C, significantly faster ascorbic acid degradation and ammonia accumulation occurred, resulting in off-flavor which was apparent after 25 days. However, storing baby kale in 10% O2 combined with 10% or 15% CO2 maintained visual quality without developing off odor or off flavor for 25 days at 5 °C. Use of modified atmosphere packaging can extend the shelf life of baby White Russian kale when it is stored and marketed at 5°C. Different result however was found in arugula. The arugula was stored at 5℃ in 5, 7, 10, or 0.03 % CO2 in combination with 15, 13, 10, or 21 % O2, respectively. Our results demonstrated that holding arugula in elevated CO2 combined with low O2 atmospheres increased its postharvest shelf life. After 13 days of storage at 5℃, the quality of arugula held in air was below the limit of marketability due to degradation. The visual quality of arugula stored in 15% CO2 and 5% O2 remained above the marketability limit until day 19 (6 days longer). High CO2 and low O2 also better maintained ascorbic acid and the aromatic volatiles, including 1-penten-3-ol and 2-hexanol that are important for the peppery and bitter flavor of fresh arugula.