Bioavailability of ascorbic acid in orange juice

Several orange-juice preparations were analyzed for biologically active and inactive ascorbic acid derivatives—L-ascorbic acid, dehydro-L-ascorbic acid, and inactive 2,3-diketo-L-gulonic acid. Fresh orange juice contained from 4 to 7 mg/100 ml of inactive ascorbic acid. In contrast, pasteurized orange juice contained from 15 to 30 mg/100 ml of inactive ascorbic acid (up to 400% more than fresh orange juice). Samples of fresh orange juice contained as much as 100% more active ascorbic acid than samples of pasteurized orange juice. There is great variability in prepared orange-juice derivatives with a substantial decrease in bioavailability of active ascorbic acid. (JAMA235:2624-2625, 1976)