Experimental design of blackberry (Rubus sp.) drying process for production of flour enriched with bioactive compounds

Summary

The blackberry drying process was studied using an experimental design with three factors, namely: sample weight (6 to 135 g), drying temperature (30 to 80 °C) and time (16 to 24 h). All samples were grounded and dried accordingly, in a convection oven with air circulation. Moisture and phenolic compounds concentration were chosen as response variables. Results showed small losses of bioactive compounds for the 80 g sample dried at 55 °C for 16 hours. Furthermore, the blackberry flour meets the Brazilian standards to moisture (maximum 15%) and can be classified as a product of high fiber content (24.33±2.88 g/100 g of flour). Bioactive compounds in the flour were quantified using spectrophotometric analysis: total phenolic of 344.94 mg GAE/100 g; total flavonoids of 182.82 Ce mg/100 g; total anthocyanins of 77.93 mg/100 g; monomeric anthocyanins of 82.41 CYD-3-G/100 g; total carotenoids of 0.322 mg/100 g and activity anti-DPPH EC₅₀ 21.2 μg/mL. These results show that blackberry flour is rich in bioactive compounds, adding nutritional value to foods and products made with this flour.

Keywords:
Phenolic compounds; Anthocyanins; Statistical analysis