Changes due to high oxygen and high carbon dioxide atmospheres on the general quality and the polyphenolic profile of strawberries

The aim of this work was to study and model the effects of refrigerated storage with high O₂ and high CO₂ atmospheres (70 kPa O₂ + 20 kPa CO₂ and 90 kPa O₂ + 10 kPa CO₂) on microbial growth, general quality attributes, and the polyphenolic compound profile of fresh strawberries. The storage of samples in 70 kPa O₂ + 20 kPa CO₂ controlled microbiological decay and slightly affected soluble solids and pH values for 20 d at 5 °C. Moreover, vitamin C and proanthocyanidin contents of these samples were kept almost constant throughout the storage period. Samples in 90 kPa O₂ + 10 kPa CO₂ controlled microbiological decay for 12 d at 5 °C, soluble solids and pH values were slightly affected, and vitamin C and proanthocyanidin contents experienced up to 15% decrease during this period. However, anthocyanins underwent a substantial increase during the first 3–5 d of storage in these samples. The highest anthocyanin accumulations occurred for pelargonidin-3-O-glucoside, pelargonidin-3-O-rutinoside, and pelargonidin-3-O-acetylglucoside, which increased by 68%, 132%, and 167%, respectively over their initial values at 5 d. Thereafter, anthocyanins content decreased gradually or remained even higher than their initial values at 12 d. This behavior was associated with a physiological response to stress and was not seen for strawberries stored at 70 kPa O₂ + 20 CO₂, probably due to its higher CO₂ concentration which was deleterious for anthocyanin stability. Flavonols, phenolic acids, and ellagitannins also experienced increases up to 130% at 5–12 d of storage in samples exposed to both atmospheres. The changes in general quality attributes were fitted with zero or first-order kinetics, and changes in individual phenolic compounds were adequately fitted with a consecutive reaction mechanism kinetic model.