Effects of cold shock intensity on physiological activity of harvested cucumbers during storage

- Cucumbers were cold shocked with different temperature and duration.
- Cold shock process was divided into dynamic and static cold shock stage.
- Effects of cold shock temperatures on preservation quality were illustrated.
- Optimal cold shocked intensity for cucumber was obtained.

Cold shock treatment (CST) with cold water at 0 °C (40 min), 3 °C (20, 40 and 60 min) and 6 °C (40 min) were conducted to evaluate the effects of cold shock intensity on the physiological activity of cucumbers, respectively. Weight loss, firmness, antioxidant enzyme (SOD, CAT and POD) activities, malondialdehyde (MDA) content and respiration rate were determined during storage at 12 °C and 90% RH. Results show that CST caused a decline in weight and firmness loss, and increased antioxidant enzyme (SOD, CAT and POD) activities and respiration rate of cucumbers. The storage quality of cucumbers with 6 °C water CST was unsatisfactory compared to that with 0 °C or 3 °C water. CST with cold water at 3 °C for 40 min was the optimal method for preserving cucumbers among all treatments tested. For improving cucumber preservation quality effectively, the optimal CST temperature should be set below a threshold value between 3 °C and 6 °C. The cold shock process can be divided into dynamic and static cold shock stage according to the temperature change in cucumber, and cucumber should experience the whole dynamic cold shock stage and appropriate static cold shock stage to obtain optimal preservation quality.