[Stability of anthocyanins in pasteurized juice of blackberry ((Rubus glaucus benth]

In this research the chemical stability of total anthocyanins in three pasteurized juices elaborated from 12% of blackberry (Rubus glaucus Benth) pulp, and addition of ascorbic acid (Formulation A: 0.1%, Formulation B: 0.05% and Formulation C: 0.01%), was evaluated by means of absorption visible spectra (400-580 nm). Physicol-chemical characterization (acidity, soluble solids content in degree Brix, pH), and count of mesophilic microorganism, fungi, yeasts, fecal coliforms (PMN/mL) and Escherichia coli, were evaluated. Sensorial parameters (color, smell, flavor) were investigated by means of un-trained panel using a hedonic scale (Fridman, P < 0.05). The study was performed during storage for 9 days. The total anthocyanins were reported as pelargonidin-3-glycoside g/L, and no significant differences were founded among the evaluated in each formulation during storage (P > 0.05). Bactocromic effect due to oxidation as not observed. Acidity (6.0-7.2 mL NaOH 0.079 N), soluble solids content (9.0-9.8 degrees Brix) and pH (3.4) did not show significant differences (P > 0.05). The microbiological evaluation showed minimum values for pasturized products (fungi CFU/mL < 10, yeast CFU/mL < 10, fecal coliforms CFU/mL < 10 and mesophilic microorganism CFU/mL between 120-140 on first day in storage). Sensorial analysis did not show significant differences (Fridman, P > 0.05).