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Oxidation of ascorbic acid in stored orange juice is associated with reduced plasma vitamin C concentrations and elevated lipid peroxides.

Johnston CS, Hale JC

Department of Nutrition, Arizona State University, 7001 E Williams Field Rd, Mesa, AZ 85212, USA. carol.johnston@asu.edu

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.

Published 6 January 2005 in J Am Diet Assoc, 105(1): 106-9.
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