OBJECTIVE: The objective of this study was to analyze the ascorbic acid stability of mandarin juice from the cultivar Ponkan under different storage conditions, and of 13 samples of processed mandarin beverages, as well as the antioxidant activity stability of fresh juice. METHODS: Fresh mandarin juice was stored under three temperatures: room temperature, refrigeration and freezing. Mandarin samples were kept under refrigeration. Thirteen brands of processed mandarin beverages were purchased and kept under refrigeration. Ascorbic acid level was determined by the Tillman's titrimetric method (Association of Official Analytical Chemists) and antioxidant activity by the radical scavenger capacity using the 2,2-diphenyl-1-picrylhydrazyl radical. RESULTS: The mean ascorbic acid level in fresh juice was 32.40mg/100mL and the reduction rate of this nutrient was higher when the samples were stored under higher temperatures. The average antioxidant activity was 89.74% of 2,2-diphenyl-1-picrylhydrazyl radical inhibition, with variations of up to 4.26% during storage. Among the processed beverages, the mean ascorbic acid content varied from 1.01 to 10.72mg/100mL, with losses of up to 82.76%. Six brands of processed beverages were considered noncompliant with the Brazilian legislation regarding the ascorbic acid content reported in the labels. CONCLUSION: Mandarin juice from the Ponkan cultivar has high antioxidant activity, even during storage. The fresh juice was nutritionally better than the processed beverages, considering ascorbic acid content and stability. Additionally, the results indicated the need of greater surveillance of nutritional labeling.
Ascorbic acid; Antioxidants; Food storage; Citrus
