Changes in respiration of fresh-cut butterhead lettuce under controlled atmospheres using low and superatmospheric oxygen conditions with different carbon dioxide levels.

摘要

The effect of low and high oxygen levels (0-100 kPa) combined with different carbon-dioxide levels (0, 10 and 20 kPa) on the respiration rate of fresh-cut butterhead lettuce stored at different commercial temperatures (1, 5 and 9 C) was determined. Controlled atmospheres (CA), as described, showed a constant respiration rate during the first 2-4 days of storage at the different temperatures selected, indicating this could be used commercially. Compared to CA storage with high oxygen levels and moderate carbon-dioxide levels, lettuce exposed to low oxygen and moderate to high carbon-dioxide levels had a higher respiration rate, probably due to the carbon dioxide causing physiological stress. Moderate carbon-dioxide levels reduced the respiration rate of the lettuce by 20-40% at 9 C, an effect that was less pronounced at the lower temperatures. The authors concluded that 80 kPa of oxygen combined with 10-20 kPa of carbon dioxide should be used in modified atmosphere packaging (MAP) of fresh-cut butter lettuce to avoid fermentation and reduce the respiration rate.