Effect of high carbon dioxide injury on the physiological characteristics of fresh-cut garlic scapes

Abstract

Garlic scapes (flower stalks of garlic) exhibited symptoms of CO2 injury when exposed to high CO2 conditions during storage. This study aimed to investigate and compare the physiological characteristics of fresh-cut garlic scapes stored in air or in a high CO2 atmosphere (21 % CO2 and 5% O2) at 25 °C. High levels of CO2 promoted the production of several enzymes associated with anaerobic metabolism, particularly PDC and ADH, which lead to the accumulation of ethanol. The content of ethanol in fresh-cut garlic scapes stored in a high CO2 atmosphere was about 5.9 times greater than that of those stored in air. High CO2 also enhanced the accumulation of other volatile compounds, alcohols, aldehydes and esters, often the primary cause of off-flavor development. The cell membrane-bound Ca2+ content of the fresh-cut garlic scapes stored in a high CO2 atmosphere was significantly lower than of those stored in air, because it had combined with CO2 thus making the content of calcium carbonate higher. This sharp decline in cell membrane-bound Ca2+ aggravated the damage to the tissue structure. The activity of PPO also increased when fresh-cut garlic scapes were stored in a high CO2 atmosphere.