The postharvest chain for blueberry is challenging. Complications are related to the monitoring of ripeness, which manifests as coloring of the peduncular area. This leads to potential degradation during storage, a decrease in bioactive components and a reduction in quality characteristics. To mitigate these complications, the impact of increased artificial UV-B radiation on nutraceutical compounds of ‘Cargo’ blueberries (Vaccinium corymbosum L.) was evaluated. Pot cultivated blueberries were harvested at a partially immature state (stalk point of insertion still green/pink) and immediately processed under UV-B. UV treatments were performed with a peak emission at 310 nm and 18.58 W m-2. Two exposure times (5 and 20 minutes) were performed in triplicate. Samples were stored for 1, 2 and 24 h at 20°C (adaptation time) in a perforated plastic box, before cold storage at 2°C for 6 days (storage time), after which the berries were qualitatively analysed. The findings show that shorter treatments and longer adaptation times provided significantly greater accumulations of anthocyanins than the control. Low irradiation (5 min) caused some distinctive changes in fruit pigmentation characterized by a color change towards darker shades compared to the control. The best treatment for retaining the quality of the berries was to hold the fruit for 2 h after treatment at 20°C. The weight loss results were significantly lower than the control during cold storage. On the other hand, the firmness of the berries declined significantly with increasing exposure to UV-B radiation. The accumulation of anthocyanin between the adaptation times were quite similar and the mechanical properties were better preserved with short UV treatments. Therefore, short adaptation times and low dosage treatments of UV-B radiation offer a means of improving the postharvest management of blueberries. These treatments should provide consumers with fully mature, defect-free, and nutraceutical compound-rich products.
Alice Varaldo won the ISHS Young Minds Award for the best poster presentation at the VII International Conference Postharvest Unlimited in the Netherlands in May 2023.
Alice Varaldo, Department of Agricultural, Food and Forest Sciences, University of Turin, Largo Paolo Braccini 2,10095 Grugliasco, Italy, e-mail: alice.varaldo@unito.it
The article is available in Chronica Horticulturae