Ozone Processing of Peach Juice: Impact on Physicochemical Parameters, Color, and Viscosity

The impact of gaseous ozone on pH, degrees Brix, titratable acidity, and optical and rheological properties of fresh squeezed peach juice was investigated. Peach juice was exposed to ozone (0.06-2.48g. L-1) in a bubble column at 20 +/- 1 degrees C. Nonsignificant or slight changes in pH, degrees Brix, and titratable acidity were found during ozonation. Lightness (L*) slightly decreased in the first minute of O-3 exposure and then remained practically constant, while a* parameter slightly increased in all treated samples. L* and a* parameters as well as Browning Index values reflected a slight increase in browning in ozonized juices. All juices, treated and untreated, exhibited non-Newtonian flow characteristics with pseudoplastic behavior. Significant reductions in apparent viscosity and a trend toward Newtonian flow as O-3 treatment time increased were observed for ozonized juices. The Power Law model was suitable to fit rheological data.