title: Oxidation of ascorbic acid in stored orange juice is associated with reduced plasma vitamin C concentrations and elevated lipid peroxides.
abstract: Ascorbic acid oxidizes in refrigerated orange juice, but the physiological relevance of this deterioration is unknown. We compared changes in plasma vitamin C and total lipid peroxides (thiobarbituric acid-reactive substances, TBARS) in the 2-hour period following consumption of commercial orange juices on day 1 vs day 8 of storage (4 degrees C). The ascorbic acid content decreased significantly after storage in juice reconstituted from frozen concentrate (117+/-8 vs 89+/-8 mg/8 fl oz, P =.001), but did not change in chilled juice (69+/-5 vs 64+/-12 mg/8 fl oz.). The mean incremental TBARS value was less on day 1 vs day 8 for juice from frozen concentrate (-0.46+/-0.72 and 0.70+/-0.53, P =.046), but did not differ for chilled juice (0.00+/-0.49 and 0.54+/-0.89). The incremental values for plasma TBARS and vitamin C in the 2-hour postprandial period were inversely related (r=-0.48, P =.017). These data indicate that the loss of ascorbic acid in refrigerated juice may impact postprandial oxidative stress.
authors.affiliation: Department of Nutrition, Arizona State University, 7001 E Williams Field Rd, Mesa, AZ 85212, USA. carol.johnston@asu.edu
authors.forename: Carol S
authors.initials: CS
authors.lastname: Johnston
authors.forename: Joanna C
authors.initials: JC
authors.lastname: Hale
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000378:metabolism*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D001628:Beverages / Q000032:analysis*; D032084:Citrus sinensis; D003080:Cold Temperature; D018592:Cross-Over Studies; D004355:Drug Stability; D005260:Female; D005511:Food Handling / Q000379:methods; D005519:Food Preservation / Q000379:methods*; D005628:Frozen Foods / Q000592:standards; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology*; D010084:Oxidation-Reduction; D019518:Postprandial Period; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D013997:Time Factors
chemical_list: D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D001205:Ascorbic Acid