Anthocyanin profile, color and antioxidant activity of blueberry (Vaccinium ashei) juice as affected by thermal pretreatment

The effects of hot water bath and steam pretreatments were investigated, considering color, anthocyanin profile and antioxidant activity of blueberry (Vaccinium ashei) juice. The juice maximum total phenolic content, anthocyanin, and antioxidant activity were observed using the steam pretreatment processing method. Eleven anthocyanins were isolated from the blueberry juice of steam treatment processing, while only 10 from the hot water bath and 8 from the control sample. After storage at 40°C for 10 days, the anthocyanin retention rate of the juice from steam treatment processing was higher than in that from hot water bath and control sample (30.71%, 23.77%, and 19.91%, respectively). The antioxidant capacity was also significantly higher and the hue angle (H°) was lower in the juice from steam pretreatment processing. Steam pretreatment process could prevent color deterioration, increase variety and content of anthocyanins, and improve antioxidant activity in the blueberry juice.