Postharvest biology and quality of fruit kept in superatmospheric oxygen atmospheres
A.A. Kader
Proceedings of 26th International Horticultural Congress. 2002. pp. 266-267.
2002
บทคัดย่อ
Oxygen concentrations greater than 21 kPa may influence postharvest biology and quality of fresh intact fruts and their fresh-cut products either directly (via the action of free radicals on the fruit tissue and/or decay-causing fungi) or indirectly (via altered carbon dioxide and ethylene production rates and/or actions). Sensitivity to oxygen toxicity varies among species, cultivars, and developmental staages of the fruti. There is no clear relationship between tolerance of fruits to high oxygen concentrations and their total antioxidant activity. Ripening of matur-green, climacteric fruits may be slightly enhanced by exposure to 30 to 80 kPa oxygen, but levels above 80 kPa may retard their ripening and induce oxygen toxicity symptoms on some fruits and aggravate chilling injury symptoms on fruits such as avocado and banana. Exposure to 80 kPa or higher oxygen concentrations can induce fermentative metabolism and associated undesirable flavor in fruits. Elevated oxygen atmospheres enhance many of the effects of ethylene on fruits, including color changes (chlorophyll degradation and biosynthesis of carotenoids and anthocyanins) and softening. Exposure of intact fruit to 40 to 80 kPa oxygen-enriched atmospheres before cutting or exposure of fresh-cut fruit products to such atmospheres has little or no efect on rattes of browning and softening of the fresh-cut products and their post-cutting life. While superatmospheric oxygen concentrations retard the growth of some fungi, they are much more effective if combined with elevated (15 to 20 kPa) carbon dioxide as a fungistatic treatment; however, the combination of elevated oxygen and elevated carbon dioxide is often no better than elevated carbon dioxide alone.