Sulfur dioxide fumigation alone or in combination with CO2-enriched atmosphere extends the market life of highbush blueberry fruit

The combined effect of sulfur dioxide (SO2) fumigation and different carbon dioxide (CO2)-enriched atmospheres (3% O2 + 3, 6, 12, or 24% CO2) on quality attributes, postharvest decay, phytochemical content, and antioxidant capacity of eight fresh blueberry cultivars (Vaccinium corymbosum L.) was determined. The SO2 treatments did not harm berry quality, but did significantly reduce decay incidence, especially when it was followed by storage in elevated CO2 atmospheres (>6%). However, very high CO2 atmospheres (24%) induced fruit softening and ‘off-flavors’. Botrytis and Alternaria spp. were the dominant fungal pathogens causing decay of blueberries during storage, but differences in the species of decay microorganisms were found among cultivars. Postharvest strategies that included SO2 fumigation and/or enriched CO2 atmospheres did not negatively affect phytochemical content or antioxidant activity of the fruit; however, the polyphenolic content and total antioxidant activity varied greatly among cultivars. Overall, SO2 fumigation followed by controlled atmosphere storage (3% O2 + 6 or 12% CO2) is a promising postharvest strategy for fresh blueberries to reduce decay, extend market life, and maintain high nutritional value.

► SO2 fumigation followed by CO2-enriched atmospheres extended market life of blueberries.
► SO2 fumigation reduced the incidence of molds causing decay on berry surface.
► High levels of CO2-enriched atmospheres (24%) induced berry softening and/or ‘off-flavors’.
► SO2 did not affect negatively blueberry quality attributes or phytochemical properties.