Changes in bioactive composition of fresh-cut strawberries stored under superatmospheric oxygen, low-oxygen or passive atmospheres

The effect of different modified atmosphere packaging conditions (2.5 kPa O2 + 7 kPa CO2, 10 kPa O2 + 5 kPa CO2, 21 kPa O2, 60 kPa O2 and 80 kPa O2) on the antioxidant properties of fresh-cut strawberries was investigated. Changes in phenolic acids, flavonoids (anthocyanins and flavonols), vitamin C and antioxidant capacity were analyzed for 21 days at 4 °C. O2, and CO2 package headspace concentrations were also evaluated. The initial quercetin content was maintained for 11–14 days regardless of the initial in-package atmospheres, but then it was dramatically enhanced in the strawberries stored at ≥21 kPa O2. High O2 concentrations inside headspace packages promoted greater losses of phenolic acids (p-coumaric, hydroxybenzoic and ellagic acid) and vitamin C during the storage period compared to low O2 levels. Anthocyanin content increased significantly beyond day 9 in strawberry wedges stored at ≤21 kPa O2, whereas it was almost constant throughout the storage in fresh-cut strawberries at superatmospheric O2 atmospheres. In general, low-O2 and passive atmospheres best maintained the initial antioxidant capacity of fresh-cut strawberries through the cold storage. Therefore, 2.5 kPa O2 + 7 kPa CO2 atmospheres are proposed to prevent oxidation of the main antioxidant compounds in fresh-cut strawberries.