Enriched ozone atmosphere enhances bioactive phenolics in seedless table grapes after prolonged shelf life

'Autumn Seedless' table grapes (Vitis vinifera L.) were stored for up to 60 days at 0 degrees C under ten different gas treatments. An additional simulated retail display period of 7 days in air at 15 degrees C was also applied in all cases. These postharvest treatments were tested as an alternative to the usual industrial SO2 application and included modified atmosphere packaging (MAP), with and without natural fungicides (hexanal and hexenal), controlled atmosphere (CA) and intermittent and continuous applications of ozone (03). The sensory quality was preserved with MAP of 13-16 kPa O-2 + 8-11 kPa CO2, CA of 5 kPa O-2 + 15 kPa CO2 and both O-3 treatments. Although 03 did not completely inhibit fungal development, its application increased the total flavan-3-ol content at any sampling time. Continuous 0.1 mu L L-1 O-3 application also preserved the total amount of hydroxycinnamates, while all treatments assayed maintained the flavonol content sampled at harvest. Total phenolics increased after the retail period in O-3-treated berries. MAP preserved the total polyphenol content, while a slight decrease was observed under the CA conditions used. Therefore the improved techniques tested for retaining the quality of 'Autumn Seedless' table grapes during long-term storage seem to maintain or even enhance the antioxidant compound content. (c) 2007 Society of Chemical Industry.