Influence of different extracts addition on total phenols, anthocyanin content and antioxidant activity of blackberry juice during storage

The aim of this study was investigation of influence of different extracts addition on total phenols, anthocyanin content, antioxidant activity and percent of polymeric colour of blackberry juice during storage of 52 days at 4 °C. Anthocyanin content of control sample (blackberry juice without extracts addition) was 149.91 mg/L. Samples with addition of extracts (olive leaf, pine bark PE 5:1, pine bark PE 95 %, green tea, red wine PE 30 %, red wine PE 4:1 and bioflavonoids had higher anthocyanin content (from 152.42 to 161.19 mg/L) in comparison to control sample. Sample with addition of bioflavonoids had the highest anthocyanin content. Samples with addition of extracts had much higher total phenol content and antioxidant activity than control sample, what was expected since extracts are rich in phenols. During storage decrease of phenols, anthocyanins and antioxidant activity occurred in higher or lesser extent, depending on extract type addition. Anthocyanin content in control sample was 119.85 mg/L. Samples with addition of bioflavonoids, olive leaf, pine bark PE 5:1 and red wine PE 4:1 had lower (from 103.44 to 118.84 mg/L), while other samples had higher (from 131.99 to 135.57 mg/L) anthocyanin content than control sample. After storage, decrease of anthocyanins was followed with increase of percent of polymeric colour, with exception of samples with addition of green tea.