EFFECT OF ATMOSPHERE COMPOSITION ON PHENOLIC PHYTOCHEMICALS OF TWO CULTIVARS OF NORTHERN HIGHBUSH BLUEBERRY

Blueberry fruit are rich in phenolics with high antioxidant activity. However, storage recommendations have not been optimized to preserve phytochemicals and antioxidant activity. The aim of this study was to evaluate the effect of atmosphere composition on the phenolic compounds during blueberry storage. Highbush blueberry (Vaccinium corymbosum) fruit from cultivars ‘Goldtraube’ and ‘Ozarkblue’ were harvested at commercial ripeness in Sever Vouga, Portugal, and stored at 4°C for 29 days under the following atmospheres: air, 2% O₂+2% CO₂; 2% O₂+15% CO₂; and 21% O₂ + 15% CO₂. Nine phenolic compounds were identified in ‘Goldtraube’ and seven in ‘Ozarkblue’. All compounds identified in ‘Goldtraube’ decreased during the storage with the exception of chlorogenic acid the levels of which increased fourfold. In ‘Ozarkblue’, delphinidin-3-O-galactoside, cyaniding-3-O-galactoside, and cyaniding-3-O-arabinoside increased during storage in 2% O₂ + 2% CO₂ (17, 31 and 45%, respectively), 2% O₂ + 15% CO₂ (11, 15 and 25%, respectively), and chlorogenic acid increased in all atmospheres (ca. tenfold). The lowest levels of phenolics were observed when fruit were stored in air. With this study we established that atmosphere composition with low oxygen content (2% O₂) improves the preservation of anthocyanins. Concerning atmospheric concentration of CO₂, there are compounds that responded better with 2% CO2 and others with 15% CO₂.