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Stability of ascorbic acid in commercially available orange juices
Carol S Johnston1, D L Bowling
1Department of Nutrition, Arizona State University East, Mesa 85212, USA.
Journal of the American Dietetic Association
|May 3, 2002
Summary
Frozen concentrate orange juice retains more vitamin C than ready-to-drink options. For optimal vitamin C, purchase ready-to-drink juices 3-4 weeks before expiration and consume within a week of opening.
Area of Science:
- Food Science
- Nutritional Biochemistry
Background:
- Vitamin C (ascorbic acid) is a vital nutrient susceptible to degradation.
- Orange juice is a common source of vitamin C, but its content can vary.
- Storage conditions and packaging affect vitamin C stability in juices.
Purpose of the Study:
- To compare the vitamin C content of reconstituted frozen orange juice concentrates with ready-to-drink (RTD) orange juices.
- To assess the impact of storage time and packaging on vitamin C levels in orange juice.
Main Methods:
- Juices (reconstituted concentrate, RTD in resealable, and RTD in non-resealable containers) were stored at 4°C.
- Reduced and oxidized vitamin C content was measured at purchase and repeatedly over 4-5 weeks.
- Statistical analyses included repeated measures ANOVA and linear regression to compare vitamin C degradation rates.
Main Results:
- Initial reduced vitamin C in reconstituted concentrate was 86 mg/cup, decreasing to 39-46 mg/cup after 4 weeks.
- RTD juices had lower initial reduced vitamin C (27-65 mg/cup) and further decreased to 0-25 mg/cup by expiration.
- RTD juices showed 2-3 times higher oxidized vitamin C; decomposition rate was ~2% per day once opened for all juices.
Conclusions:
- Reconstituted frozen orange juice concentrates generally retain higher levels of reduced vitamin C compared to RTD juices.
- To maximize vitamin C intake from RTD orange juice, purchase 3-4 weeks before expiration and consume within one week of opening.