Impact of industrial processing and storage on major polyphenols and the antioxidant capacity of tropical highland blackberry (Rubus adenotrichus)

Critical steps of a typical industrial line for processing a blackberry-based beverage in glass bottles have been studied, together with the effects of storage of final product at four different temperatures. For the steps, contents of total phenolics, anthocyanins, ellagitannins, and minor phenolic compounds were assessed by HPLC-DAD and antioxidant capacity by H-ORAC and DPPH. Thermal processes, especially blanching, drastically reduced anthocyanins, whereas hot-filling degraded ellagitannins. The final product showed reduced values for the anthocyanins cyanidin-3-glucoside (by 52%) and cyanidin-3-malonyl glucoside (64%), and ellagitannins lambertianin C (80%), and sanguiin H-6 (50%). Antioxidant capacity (H-ORAC) dropped by almost 47%. The anthocyanins and ellagitannins continued degrading during storage, especially if temperatures were high. Reduction kinetic parameters during storage were estimated for anthocyanins and, for the first time, for both lambertianin C and sanguiin H-6.