Influence of a Sulphur Dioxide Active Storage System on the Quality of Ribes rubrum L. Berries

The aim of this study was to evaluate the post-harvest changes in the quality of red currants (Ribes rubrum L.) cv. ‘Rovada’ after 60 days of storage under modified atmosphere packaging (MAP) conditions. The storage unit was a pallet, and two treatments were performed. The CO2 -MAP treatment was used as a control, while the SO2 -MAP treatment was CO2 -MAP plus SO2 . The initial gas composition was 15.0 kPa O2  and 10.0 kPa CO2  inside all MAPs, while SO2 -generating active sheets were added to pellets in SO2 -MAP treatment. Weight loss, total soluble solid content, titratable acidity, total phenolic and anthocyanin contents, antioxidant activity, microbial count, and visual and sensorial appearance were monitored after 30 and 60 days. The results showed that berries stored with SO2 maintained the quality parameters for up to 60 days. Exposure to SO2  was effective in controlling yeast evolution, reducing the population both at 30 and 60 days at one and two orders of magnitude, respectively. Red currants stored under SO2  MAP obtained better visual quality score compared to CO2  MAP-treated berries throughout storage. Active emitters of SO2 , such as those proposed in this study, can be promising solutions to improve the post-harvest storage of red currants and the berries marketability.