| Abstract
| - Freshly squeezed orange juice samples were ozonated with control variables of gas flow rate (0−0.25 L min−1), ozone concentration (0.6−10.0%w/w), and treatment time (0−10 min). Effects of ozone processing variables on orange juice quality parameters of pH, °Brix, titratable acidity (TA), cloud value, nonenzymatic browning (NEB), color values (L*, a*, and b*), and ascorbic acid content were determined. No significant changes in pH, °Brix, TA, cloud value, and NEB (p< 0.05) were found. L*, a*, and b* color values were significantly affected by gas flow rate, ozone concentration, and treatment time. The changes in lightness (L*) values and total color difference (TCD) values were fitted well to zero-order kinetics, whereas a*, b*, and ascorbic acid degradation followed first-order kinetics. The rate constants for a*, b*, and TCD were linearly correlated with ozone concentration (R2 = 0.88−0.99), whereas the rate constants for L* and ascorbic acid were exponentially correlated (R2 = 0.94−0.98).
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