Influence of γ-irradiation on the reactive-oxygen metabolism of blueberry fruit during cold storage

- Blueberry irradiated by 1.0 kGy to 2.5 kGy doses had better preservation effect.
- 1.0 kGy to 2.5 kGy irradiation doses inhibited the respiration and LOX activity.
- The appropriate irradiation treatment can improve the activities of SOD, CAT and POD.
- The contents of O2− and H2O2 in irradiated blueberries were kept in a lower level.

To explore a safe, environmentally friendly, and efficient preservation technology for blueberry (Semen trigonellae), “Bluecrop” blueberry fruits were treated with different irradiation doses. During cold storage at 0 ± 5 °C, the decay rate, fruit firmness, and indices relating to respiration and reactive-oxygen metabolism were detected regularly. Results showed that irradiation treatment with 1.0 kGy to 2.5 kGy doses was able to inhibit the respiration intensity, ethylene production, and the improvement of lipoxygenase (LOX) activity, thus reducing the increase of malondialdehyde (MDA) content and the permeability of cell membranes. In addition, irradiation treatment can improve the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) to eliminate, on a continual basis, the constantly generated superoxide anions (O2−) and hydrogen peroxide (H2O2), keeping them at a low level: ultimately, this effectively guaranteed the storage quality and postponed the senescence process in the blueberry fruits. Meanwhile, those irradiated at 2.5 kGy presented optimal preservation effects as the respiration was inhibited to the utmost extent and the anti-oxidisation effect was enhanced. The results prove that the 60Co γ-irradiation treatment at proper doses is an effective method of storing post-harvest blueberry fruits at low temperatures.