The Change of Total Anthocyanins in Blueberries and Their Antioxidant Effect After Drying and Freezing

[摘要] This study examined the effects of freezing, storage, and cabinet drying on the anthocyanin content and antioxidant activity of blueberries (Vaccinium corymbosumL). Fresh samples were stored for two weeks at5∘C while frozen samples were kept for up to three months at−20∘C. There were two drying treatments, one including osmotic pretreatment followed by cabinet drying and the other involving only cabinet drying. Total anthocyanins found in fresh blueberries were7.2±0.5mg/g dry matter, expressed as cyanidin 3-rutinoside equivalents. In comparison with fresh samples, total anthocyanins in untreated and pretreated dried blueberries were significantly reduced to4.3±0.1mg/g solid content, 41% loss, and3.7±0.2mg/g solid content, 49% loss, respectively. Osmotic treatment followed by a thermal treatment had a greater effect on anthocyanin loss than the thermal treatment alone. In contrast, the frozen samples did not show any significant decrease in anthocyanin level during three months of storage. Measurement of the antioxidant activity of anthocyanin extracts from blueberries showed there was no significant difference between fresh, dried, and frozen blueberries.

[学科分类] 基础医学