Changes in antioxidative metabolism accompanying pitting development in stored blueberry fruit

Blueberries (Vaccinium spp. ‘LanFeng’) are harvested and consumed at maturation and have a short storage life at room temperature. Changes in blueberry quality and physiological parameters differ under room or low temperature storage conditions. The storage life of blueberries can be extended at low temperature, but pitting can develop associated with refrigeration, especially during subsequent shelf-life. The objective of this research was to understand the antioxidative metabolism accompanying pitting development of stored blueberry fruit, involving reactive oxygen species and antioxidant systems. Physiological and metabolic disorders, including low firmness, increased cell membrane electrolyte leakage and malondialdehyde (MDA) content, and changes in enzyme activity, were observed in pitting blueberries. Blueberries were stored at 20 °C and 0 °C for 10 days and 60 days, respectively. Hydrogen peroxide and superoxide radical production rate increased more rapidly during shelf-life after cold storage than at room temperature. On the other hand, blueberries during shelf-life after cold storage, when pitting occurred, had lower activity of antioxidant-related enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), than those stored at room temperature. The severity of pitting was paralleled by higher cell membrane electrolyte leakage and MDA content, and lower SOD, CAT, and APX activities.