Abstract:

Postharvest Shatangju （Citrus Reticulata Blanco CV. Shiyueju） fruit are susceptible to chilling injury, which results in quality reduction of pulp. However, the mechanism of quality reduction has not been well understood yet. Shatangju fruit were stored at 1℃, 3℃, 6℃ and 9℃.The storage effect, pulp quality and physiological responses were compared to each other. The results indicated that chilling injury symptom occurred in the fruit stored at 1℃ or 3 ℃，and 6℃ was the optimum temperature for storage. Chilling injury not only reduced the appearance quality of the fruit, but also resulted in accumulation of aldehyde and ethanol, and led to unpleasant favor and quality reduction in pulp. Compared with the fruit stored at 6℃, the respiratory rate, ethylene production, the content of malondialdehyde (MDA), the activities of pyruvat decarboxylase (PDC) and alcohol dehydrogenase (ADH) increased dramatically in the fruit stored at 1℃. It was suggested that, during chilling temperature storage, the quality reduction of pulp is due to the accumulation of aldehyde and ethanol, and the increase of respiratory rate may be due to the increase of PDC and ADH activities.

Key words: citrus, low temperature storage, chilling injury, pyruvate decarboxylase, alcohol dehydrogenase