Abstract:This study aimed to investigate the effects of dynamic controlled atmosphere (O2=0.90%~1.25% and CO2=0.06%~0.17%) on the real-time ethylene content of 'Bartlett' pears in comparison with commercial controlled atmosphere (CA) (O2=2.25% and CO2<0.10%). The effects of each controlled atmosphere on the fruit quality and physiological disease occurrence for the fruits from different orchards stored at 20 ℃ for 1 day and 5 days after being taken out from the storage chamber for packaging (December 3, 2019 and January 21, 2020). Based on the relationship between the real-time ethylene quantity and the incidence of brown spot disease, the optimal timing for taking the fruit out of the dynamic controlled atmosphere for packaging was predicted. Compared to the pears from 6 orchards in the commercial CA room (CA 23), the ethylene content of the pears from 6 orchards in the dynamic CA room (CA 24) decreased by 42.12% during storage. The dynamic CA treatment significantly inhibited the degradation of peel chlorophyll (p<0.05) after 1 and 5 d of storage at 20 ℃, and the incidence of brown spots after 5 d of storage at 20 ℃ (p<0.05), whilst causing no changes in the ethylene production rate, fruit firmness, softening potential, soluble solids content, and titratable acid. Upon the second out-for-packing, the average incidence of brown spots for the fruits in CA 23 was 30.00% (which reached the commercially unacceptable range, 30.00%), whilst the average incidence of brown spots for the fruits in CA 24 was 17.04%. According to the linear relationship between the real-time ethylene cumulative quantity and the incidence of brown spots, the average incidence of brown spots for the fruits in CA 24 would be 30.00% on March 7, 2020. Compared to the commercial CA treatment, the dynamic CA treatment extends the fruit storage life by 1 month, indicating that the dynamic CA treatment is more valuable for commercial applications.
