Effects of long-term storage on highbush blueberry (Vaccinium Corymbosum L.) antioxidant quality

Blueberry (Vaccinium corymbosum L.) is a fruit crop rich in antioxidants. The quality of this fruit and the content of health-promoting compounds are influenced by many factors, such as environmental conditions, genetic diversity and degree of maturity at harvest. Blueberry has often been reported to be a highly perishable fruit, thus its commercial value could be strongly affected by storage conditions. After harvest, blueberry quality and product losses are mainly due to dehydration, weight loss, shrivel and fungal spoilage. Little is known so far about the effects of long-term storage on the antioxidant components of blueberry. We investigated the effects of two different conditions of controlled atmosphere (CA1: 4 kPa O2 plus 10 kPa CO2; CA2: 1 kPa O2 plus 9 kPa CO2) on a mid/late season blueberry cultivar (‘Legacy’) during long-term storage, by measuring the incidence of decay, total polyphenols, total flavonoids, total anthocyanins and the antioxidant capacity using the DPPH˙ radical-scavenging assay. Sampling was for a period much longer than normally expected for storage of this product. Controlled atmosphere unexpectedly did not retard decay. During storage an irregular pattern was observed in the levels of total polyphenols, but at the end of the trial, the content had not changed, with respect to the beginning, in the control and CA2 stored samples. The content of total flavonoids and total anthocyanins changed in a similar way during storage and no marked effect can be linked to any gas composition. In conclusion ‘Legacy’ blueberry fruit demonstrated stability in quality attributes and marketability during the whole cold storage period (almost 5 months). ‘Legacy’ appeared to be a rich source of phenolic compounds. Among the different applied CA conditions, CA2 was slightly more effective in maintaining high levels of flavonoids and anthocyanins.