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Vitamin C, fruit acids and natural colors in juice drinks

Separate redox, pH, base and processing effects with controlled samples.

Prepared by Colorwell · Localized 2026-09-11

Break the formula into variables

Vitamin C, citric or malic acid, juice concentrate, minerals and flavor often occur together. A single finished sample cannot identify which contribution changes the shade.

Vitamin C depends on the system

It changes the redox environment and may protect color in one formulation while contributing to change in another. Use the same formula with and without vitamin C rather than assuming one direction.

Acid and the base matter

Fruit acids affect pH and buffering. Anthocyanin and radish-red systems are pH-responsive, while beetroot red also interacts with heat, light and oxygen. Record acid-addition order as well as final pH. Juice contributes its own color, minerals and phenolics; clean water cannot replace it.

Minimum screening direction

Keep an uncolored actual base, a no-vitamin-C sample and the intended-vitamin-C sample. Add controlled pH, heat and light/package comparisons. Define target hue and pH before comparing beetroot red, carmine, radish red or blends. Judge post-heat, post-light and shelf behavior with the actual market requirements.

References and source material

Adapted from the Chinese source

Original Chinese article — Colorwell

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