Antioxidant capacity, total phenolic content and phenolic compounds of pulp and bagasse of four Peruvian berries.

Revaluing agri-food waste to offer consumers bioactive compounds for a healthy diet is an important issue. In the present work, the antioxidant capacity (AC), total phenolic content (TPC) and phenolic compounds of pulp and bagasse of four Peruvian berries with UHPLC-DAD was determined. Elderberry (Sambucus peruviana Kunth) bagasse had a greater amount of TPC (4.87 ± 0.02 mg GAE/100 gfw) and AC (7.66 ± 0.04 and 7.51 ± 0.24 µmol TE/gfw in DPPH and ABTS, respectively) than the bagasse of the other berries, with a strong positive correlation between TPC and AC. Blueberry (Vaccinium floribundum Kunth) bagasse contains the highest amount of gallic acid (103.26 ± 1.59 µg/gfw), chlorogenic acid (1276.55 ± 1.86 µg/gfw), caffeic acid (144.46 ± 1.78 µg/gfw), epicatechin (1113.88 ± 1.82 µg/gfw) and p-coumaric acid (77.82 ± 1.92 µg/gfw). Elderberry (Sambucus peruviana Kunth) bagasse contains the highest amount of catechin (153.32 ± 0.79 µg/gfw). No significant differences were found in the content of chlorogenic acid and epicatechin of blackberry (Rubus roseus Poir). It was shown that the wastes of the four Amazonian berries have higher values of bioactive properties than their pulp, being the elderberry bagasse the one with the best properties.

Kinetics Drying of Blackberry Bagasse and Degradation of Anthocyanins and Bioactive Properties.

The process of drying food is necessary to preserve it; however, some bioactive compounds can be degraded during drying process. In this work, the convective drying process of Peruvian blackberry bagasse and the degradation of anthocyanins, total phenolic content (TPC), and antioxidant capacity (AC) were studied. The logarithmic model fitted well to the data and could predict the process, showing that 6 h of drying at 90 °C is enough to reach equilibrium moisture. Anthocyanin degradation followed a first-order kinetic model with reaction rate constant between 5.45 × 10-2 ± 4.68 × 10-3 and 1.21 × 10-1 ± 2.31 × 10-2 h-1, and activation energy of 25.11 kJ/mol. The highest retention (84.38%) of anthocyanins was obtained in 1 h at 50 °C and the highest degradation (68.54%) in 6 h at 90 °C. The TPC and AC increased with the drying time and temperature due to the increased water evaporation.