5

Vitamin C is a fragile micronutrient [1,2]. Any manipulation of the fruit which contains it, can destroy it.
Let's talk for orange juice, for example.

Virtually, staring with harvesting of the orange, vitamin C degrades.
And this trend continues due to mechanical (squeezing), thermal (pasteurisation) and chemical (adding preservatives) treatments when the orange juice is made.
Furthermore one should take into account orange juice that has been placed into a bottle, stays on the supermarket shelf for weeks, after it has been transported from the made factory to the supermarket.

And the question born of your own accord: how much of the vitamin C listed in the nutritional label is actually in the orange juice I drink?

Long story short: how much vitamin C is actually present in a glass of orange juice, taking into account could have been passed months since harvesting-squeezing-bottling to drinking?
Is the nutritional label correct?


[1]: https://doi.org/10.1016/j.jfoodeng.2005.03.026
[2]: https://pdfs.semanticscholar.org/aaf2/a74bc38ed53ded06d673ac23baf75c2a949f.pdf


This question worth for other vitamins and other susceptible micronutrients in other foods, as well.

2

Question: How much vitamin C is actually present in a glass of orange juice, taking into account could have been passed months since harvesting-squeezing-bottling to drinking?

The nutrition label of the bottled juice should tell what is in the bottled juice after harvesting-squeezing-bottling. USDA.gov has evaluated the amount of vitamin C in many brands of orange juices, which can make you believe they evaluated the actual bottled orange juices from the shelves in stores.

After putting the orange juice on a shelf (According to ScienceDirect):

In general, degradation of vitamin C is a function of time.

In this study they concluded it is time, room temperature, exposure to light and the addition of sugar that can affect the amount of vitamin C in fruit juices:

...were stored for 28 days at 37 °C. After 14 days of storage, ascorbic acid was completely degraded...

...retention of L-ascorbic acid is greatly affected by the storage temperature (4–50 °C).

As a side note, here's a chart from NutritionData that tells how freezing, drying, cooking and reheating affect the amount of vitamin C in a food.

Here's one study about vitamin C degradation in milk, just to show that you really need a lot of data to make final conclusions:

The use of a 3-layered opaque bottle was associated with complete oxidation of vitamin C after 1 month of storage, whereas in the 6-layered opaque bottle, which has an oxygen barrier, the vitamin C content slowly decreased to reach 25% of the initial concentration after 4 months of storage.

| improve this answer | |
  • 2
    Storage at 37°C is never good for anything; and unrealistic. People often drink OJ for the VitC, labels often say that the pack is 'good' for quite a long time – at room or storage temp, not freezing temp. So, do you have more numbers for storage at 4, 14, 20°C? – LаngLаngС Oct 6 '18 at 9:36
  • Yes, storing a juice at 37 °C is really strange. Anyway, the numbers are in the studies and I find it completely unrealistic to quote them here because there are too many other factors involved: time, exposure to light, sugar, other nutrients from the fruit... – Jan Oct 6 '18 at 9:45
  • They are difficult to estimate. But for realistic: I would conclude from the above that once juiced (& up-vit-c-ed, usually) for ascorbic acid the juice gets almost worthless after 4 weeks at room temperature and should be stored in the fridge before being opened? – LаngLаngС Oct 6 '18 at 9:49
  • 1
    I added results of one study regarding vitamin C degradation in milk: the additional factor is the type of a package. – Jan Oct 6 '18 at 10:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.