Pigments and antioxidant activity of optimized Ready-to-Drink (RTD) Beetroot (Beta vulgaris L.)- passion fruit (Passiflora edulis var. flavicarpa) juice blend

A central composite rotatable design (CCRD) was employed to optimize the beetroot-passion fruit blended juice. The independent variables were beetroot juice (30-70 ml), passion fruit juice (10-30 ml) and sucrose (9.00-10.50g). The combined effect of these independent variables on pH, °Brix and overall acceptability were investigated. Results showed that the generated regression models adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses. The optimized blended juice was prepared in bulk, thermally pasteurized and studied the effects on pigments, antioxidant activity, CIE Color (L*, a*, b*, E*), Browning Index*, native microflora and other physicochemical quality parameters were also evaluated during the storage at 27-30 ± 2 °C. The processing and storage had a significant effect on (p < 0.05) degradation in the pigments, antioxidant activity during storage. The decrease in antioxidant activity was correlated (r = 0.9895) with a decrease in betalain pigment. The product was safe from microflora after thermal pasteurization and during 180 days of storage with good sensory acceptability.