Comparing E129 - Allura red vs E124 - Ponceau 4r
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Found in 26,926 products
Found in 14 products
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Interest over time for 12 keywords in U.S. during the last 10 years.
Interest over time for 6 keywords in U.S. during the last 10 years.
Popular questions
Why is red 40 bad?
Concerns focus on it being a synthetic azo dye and on studies suggesting small effects on attention and activity in some children (the EU requires a behavior warning label for E129). It may also trigger rare hypersensitivity reactions, though regulators (FDA, EFSA, JECFA) consider it safe at approved levels.
Why is red 40 banned?
It isn’t broadly banned—FD&C Red No. 40 is allowed in the U.S. and EU (with an EU warning about possible effects on children’s behavior). Some jurisdictions, schools, or brands choose to avoid it, but that’s a policy choice rather than a general prohibition.
What is red 40 made of?
Allura Red AC is a synthetic azo dye produced from petroleum‑derived aromatic compounds, typically used as its water‑soluble sodium salt (also available as calcium/potassium salts or aluminum lakes).
What does red 40 do to your body?
Most ingested Red 40 is not absorbed and is excreted; some is broken down by gut bacteria to aromatic amines. In sensitive individuals it can cause intolerance-like reactions, and some children may experience small, reversible changes in activity/attention; within the ADI (~7 mg/kg body weight/day) it’s considered safe by major regulators.
What is red dye 40 made of?
It’s a synthetic azo dye made from petroleum‑derived aromatic compounds, usually supplied as the water‑soluble sodium salt (and sometimes as calcium/potassium salts or aluminum lakes).
How does ponceau stain work?
In labs, “Ponceau stain” usually means Ponceau S (not the food color E124 Ponceau 4R); it’s an anionic azo dye that reversibly binds proteins on nitrocellulose or PVDF via electrostatic and hydrophobic interactions, giving red bands. As a similar sulfonated azo dye, E124 would color proteins non‑specifically by the same principle but isn’t the standard reagent.
How to image ponceau stained membrane?
Rinse to lower background, then image the wet membrane under white light with a flatbed scanner, gel imager, or phone camera—no special filters needed. After imaging, destain with water or TBST before immunodetection.
How to make ponceau s solution?
Ponceau S (different from E124) is typically prepared as 0.1% w/v dye in 5% v/v acetic acid in water; mix to dissolve and filter. Store at room temperature; optionally include ~0.1% SDS to speed staining.
How to make ponceau stain?
For protein blots, use Ponceau S: 0.1% w/v in 5% v/v acetic acid (water), filter, and use to briefly stain the membrane. E124 Ponceau 4R is a food colorant and isn’t standard for this application.
How to remove ponceau stain?
Wash the membrane in water or TBST until the red color disappears (typically 1–5 minutes); the staining is fully reversible and compatible with later antibody probing. If background persists, a brief rinse in dilute base (e.g., ~0.1 M NaOH) can clear it quickly.