Abstract
Changes in the 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and the ascorbic acid content of commercial beverages (green tea, vegetable juice, sport drink, and coffee) during preservation were investigated. The beverages were preservedat 5°C,25°C, and 35°C in the air or in a vacuum. The decrease in radical-scavenging activity and ascorbic acid content was found to be greater with increasing preservation temperature, this being more apparent in the air than in a vacuum. Long-term preservation, however, resulted in the radical-scavenging activity and ascorbic acid content decreasing even at a low temperature in a vacuum. Those beverages with a higher content of sugar retained a high level of ascorbic acid, which may have been due to the protective effect of sugar against ascorbic acid oxidation.
