| Research Abstract |
1. The relationship between low O_2 injury and ethanolic metabolism in twenty kinds of fruits and vegetables were investigated. A visible injury, skin pitting, appeared in okra, cucumber and eggplant fruit, while discoloration occurred in Chinese chive leaves, cauliflower, spinach leaves, eggplant and pear fruit. In addition, water-soaked tissue appeared in spinach leaves, cauliflower, cucumber, eggplant and pear fruit Significantly, off-flavor or off-odor was detected in all commodities. Hence, the occurrence of off-flavor or off-odor is the most common and important detrimental symptom that limits tolerance of fruits and vegetables to low O_2.
2. Bell pepper fruits, Japanese pear ‘Kosui' fruits, tomato fruits and Chinese chive leaves were stored under low O_2 atmosphere to study the regulation of ethanolic fermentation. At 0% O_2, ethanol (EtOH) and to a lesser extent acetaldehyde (AA), rapidly accumulated in the tissue. Pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities, greatly increased in tissue exposed to 1% O_2.
3. Chinese chive leaves were stored under high CO_2 atmosphere to study the regulation of ethanolic fermentation. At 30% CO_2, EtOH rapidly accumulated in the tissue. Pyruvate content temporarily increased in leaves exposed to 30% CO_2, while succinate dehydrogenase activity in leaves exposed to 30% CO_2 greatly decreased.
4. Bell pepper fruits were stored under low oxygen atmosphere for 3 days then returned to air. AA of fruits exposed to 0% O_2 rapidly accumulated in the tissue during storage, while after transfer to air, AA content slowly decreased. Whereas EtOH content rapidly increased during storage, but then rapidly declined after transfer to air. ADH activity of fruits exposed to 1% O_2 rapidly increased during storage, and after transfer to air, ADH activity maintained. Whereas superoxide dismutase activity of fruits exposed to 1% O_2 increased after transfer to air.
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