Effect of UV-C treatment on chilling injury and flavor quality of Solanum muricatum fruit during storage

Objective  To study the effects of UV-C treatment on chilling injury and flavor changes of pepino (Solanum muricatum) fruit during storage, and provide a new technique and theoretical basis for postharvest storage and chilling injury prevention of pepino fruit.

Method  Pepino fruits were stored at different temperatures (0, 5, 10, 15, 20 ℃) for 15 days, and the changes in chilling injury index, sensory quality, respiration intensity, and ethylene production during storage were measured to verify pepino fruits would have chilling injury when stored at 5 ℃ and below. Further pepino fruits were treated with UV-C at doses of 0.25, 0.50 and 1.00 kJ·m⁻² respectively, and stored at 5 ℃ for 15 days. The changes in chilling injury and flavor quality during storage were measured, combining with measurement of the changes of flavor substances using the electronic nose.

Result  Under 5 ℃ cold stress, the different doses of UV-C treatment effectively maintained the flavor quality, alleviated the symptoms of chilling injury and inhibited the respiration intensity and ethylene production at low temperature of pepino fruits. The ethylene production of 1.00 kJ·m⁻² UV-C treatment was 46% lower than that of the control group on the 15th day of storage, and the chilling injury index of 1.00, 0.50 and 0.25 kJ·m⁻² UV-C treatments were 30%, 70% and 67% respectively, which were significantly lower than that of the control group (81%). The 1.00 kJ·m⁻² UV-C treatment could significantly delay the onset of chilling injury for six days. Through linear discriminant analysis and radar analysis, it was found that the different doses of UV-C treatment kept the volatile aroma components of pepino fruits well.

Conclusion  Under cold stress, the different doses of UV-C treatment could significantly decrease the symptoms of chilling injury, maintain the flavor quality during storage to varying degrees, and delay the senescence of pepino fruits. Compared with other treatments, pepino fruits treated with 1.00 kJ·m⁻² UV-C have lower chilling injury index during storage and the treatment effect is the best.