title: Kinetics of freshly squeezed orange juice quality changes during ozone processing.
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, degrees 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, degrees 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 ( R (2) = 0.88-0.99), whereas the rate constants for L* and ascorbic acid were exponentially correlated ( R (2) = 0.94-0.98).
authors.affiliation: Biosystems Engineering, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Brijesh K
authors.initials: BK
authors.lastname: Tiwari
authors.forename: Kasiviswanathan
authors.initials: K
authors.lastname: Muthukumarappan
authors.forename: Colm P
authors.initials: CP
authors.lastname: O'Donnell
authors.forename: P J
authors.initials: PJ
authors.lastname: Cullen
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis / Q000737:chemistry; D001628:Beverages / Q000032:analysis*; D032084:Citrus sinensis / Q000737:chemistry*; D005511:Food Handling / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D015416:Maillard Reaction; D010126:Ozone; D011786:Quality Control
chemical_list: D010126:Ozone; D001205:Ascorbic Acid