Relationship between activated oxygen metabolism and browning of "Yali" pears during storage

This study investigated how metabolism of active oxygen is involved in core browning of "Yali" pears during storage. "Yali" pears from early, middle, and late harvests were stored under rapid or slow cooling regimes. It was shown that the delayed core browning under slow cooling regime was associated with high activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), low activity of lipoxygenase (LOX), delayed membrane lipid peroxidation, suppressed accumulation of malondialdehyde (MDA), O2-center dot and H2O2, and reduced cell membrane damage. In contrast, rapid cooling enhanced the process of core browning. Fruit from the late harvest developed severe core browning associated with membrane lipid peroxidation and lower activities of SOD, CAT, POD, and GR. Fruit from the middle harvest maintained high SOD, CAT, POD, and GR activities and low level of active oxygen, correlative to lowest core browning. Practical applications Moderate maturity at harvest and slow cooling storage are the best combination to inhibit core browning of "Yali" pears through suppressing the accumulation of activated oxygen. The results can help guide farmers in production and aid in producing higher quality produce.